An effective coherence measure to determine topical consistency in user-generated content

When searching for blogs on a specific topic, information seekers prefer blogs that place a central focus on that topic over blogs whose mention of the topic is diffuse or incidental. In order to present users with better blog feed search results, we developed a measure of topical consistency that is able to capture whether or not a blog is topically focused. The measure, called the coherence score, is inspired by the genetics literature and captures the tightness of the clustering structure of a data set relative to a background collection. In a set of experiments on synthetic data, the coherence score is shown to provide a faithful reflection of topic clustering structure. The properties that make the coherence score more appropriate than lexical cohesion, a common measure of topical structure, are discussed. Retrieval experiments show that integrating the coherence score as a prior in a language modeling-based approach to blog feed search improves retrieval effectiveness. The coherence score must, however, be used judiciously in order to avoid boosting the ranking of irrelevant but topically focused blogs. To this end, we experiment with a series of weighting schemes that adjust the contribution of the coherence score according to the relevance of a blog to the user query. An appropriate weighting scheme is able to improve retrieval performance. Finally, we show that the coherence score can be reliably estimated with a sample exceeding 20 posts in size. Consistent with this finding, experiments show that the best retrieval performance is achieved if coherence scores are used when a blog contains more than 20 posts.     

Improving English verb sense disambiguation performance with linguistically motivated features and clear sense distinction boundaries

This paper presents a high-performance broad-coverage supervised word sense disambiguation (WSD) system for English verbs that uses linguistically motivated features and a smoothed maximum entropy machine learning model. We describe three specific enhancements to our system’s treatment of linguistically motivated features which resulted in the best published results on SENSEVAL-2 verbs. We then present the results of training our system on OntoNotes data, both the SemEval-2007 task and additional data. OntoNotes data is designed to provide clear sense distinctions, based on using explicit syntactic and semantic criteria to group WordNet senses, with sufficient examples to constitute high quality, broad coverage training data. Using similar syntactic and semantic features for WSD, we achieve performance comparable to that of human taggers, and competitive with the top results for the SemEval-2007 task. Empirical analysis of our results suggests that clarifying sense boundaries and/or increasing the number of training instances for certain verbs could further improve system performance.

High-Tin Bronze Gong Making

Over the last twenty years, there has been a discernable increase in the number of scholars who have focused their research on metal production, working and use in antiquity, a field of study which has come to be known as archaeometallurgy. Materials scientists and conservators have worked primarily in the laboratory while archaeologists have conducted fieldwork geared to the study of metal technology in a cultural context with laboratory analysis as one portion of the interpretive program.     

A High-Strain-Rate Alumina-Based Ceramic Composite

An alumina-based ceramic codispersed with zirconia and mullite was synthesized with a submicron grain size. At high temperatures, steady-state creep with very limited grain growth was achieved for samples with 40 vol% alumina, 30 vol% zirconia, and 30 vol% mullite (AZ30M30). Constant stress compressive creep behavior of AZ30M30 showed a stress exponent of 2 and an activation energy of 880 kJ/mol. A strain rate of 0.01 s⁻¹ was obtained for AZ30M30 at 60 MPa and 1500°C, indicating the potential for high-strain-rate superplasticity.     

Improvement of turn structure prediction by molecular dynamics: a case study of {alpha}1-purothionin

Because of the problems in predicting a correct conformationfor loop regions in homology-based prediction, disagreementsare often found between the predicted models and the refinedX-ray structures of the same protein in loop regions. Such asituation has been encountered for ₁-purothionin (₁-PT). Hence,attempts have been made to improve the predicted model of ₁PTby limited molecular dynamics using both AMBER and XPLOR. Withmolecular dynamics, the previously predicted incorrect turnregion reverts to the correct conformation as seen in the X-rayrefined structure. In contrast to the model which is not subjectedto molecular dynamics, the improved model refines with the X-raydata of ₁PT in fewer cycles, without any manual rebuilding andwith comparable or better refinement statistics. Also, the improvedmodel serves as a better starting model in the determinationof the structure with the molecular replacement methods.     

Recent coal-fire and land-use status of Jharia Coalfield,India from satellite data

The Jharia Coalfield (JCF) in India is known for its high grade coal and associated coal fires. Before it can be exploited, valuable coal reserves are destroyed in the sub-surface due to fire. The combined act of fire and subsidence has endangered the environmental safety of the JCF, although several methods have been adopted to control the coal fires. Coal fire is a dynamic phenomenon, hence, its location and extent changes with time. To control the coal fires effectively, the status of the fires and the landscape must be assessed periodically. In this study, the thermal band in Landsat-7 Enhanced Thematic Mapper Plus (ETM+) data (daytime) of 29 March 2003 and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data (night-time) of 9 October 2006 are used to delineate the coal-fire areas. The kinetic temperature of the coal fire-affected areas is calculated from Landsat-7 ETM+ data using a Normalized Difference Vegetation Index (NDVI)-derived emissivity model, and from band 13 of ASTER data with a fixed emissivity value. The study showed that the eastern part of the JCF is more affected by coal fires than the western part. The affected collieries in the eastern part are Kusunda, Lodna, Bararee, Gonudih and Ena. Among all collieries, Kusunda is the most affected by coal fires (29% of the area) and showed a 0.56 km² increase in fire area from the year 2003 to 2006. During this period, a total increase in coal-fire area of 0.51 km² occurs in the JCF. The land-use map prepared from Indian Remote Sensing (IRS) Satellite-P6 Linear Imaging Self-scanning Sensor (LISS)-III data showed that 6.9% of the area in the JCF is occupied by mining-related activities, which indicates its vulnerability to environmental degradation.     

An intercomparison of three remote sensing-based energy balance models using Large Aperture Scintillometer measurements over a wheat-corn production region

This paper compares three remote sensing-based models for estimating evapotranspiration (ET), namely the Surface Energy Balance System (SEBS), the Two-Source Energy Balance (TSEB) model, and the surface temperature-vegetation index Triangle (TVT). The models used as input MODIS/TERRA products and ground measurements collected during the wheat and corn growth period in a subhumid climate at a measurement station in Yucheng, China. MODIS land surface temperature (LST) and leaf area index (LAI) products, corrected using ground-truth observations, were used in the three models. The TSEB model output of sensible (H) and latent (LE) heat fluxes were in good agreement with Large Aperture Scintillometer (LAS)-measured H and LE derived by residual (RMSD < 45 W/m²). Reasonable agreement was also obtained with the SEBS model output yielding RMSD for H of ~ 40 W/m² and LE ~ 55 W/m². However, the TVT model output resulted in poor agreement with the LAS-estimated H and LE with RMSD-values > 110 W/m². Using the uncorrected MODIS LST and LAI products resulted in a deterioration of the agreement in H and LE with LAS-estimated values for both the TSEB and SEBS models, whereas TVT performance improved marginally. These results indicate that the TSEB model yielded the closest agreement with the LAS-estimated fluxes using either the corrected or uncorrected MODIS inputs (LST and LAI). The SEBS model also computed reasonable H and LE values but was significantly more sensitive to errors in MODIS LST and LAI inputs than the TSEB model. In the TVT model, output of H and LE was unacceptable in either scenario of MODIS input which was attributable to errors in selection of the dry edge. With the TVT method, accurate determination of the dry edge end member is critical in regional ET estimation, but for humid and subhumid regions this end member may often be quite difficult to identify or encompass within a satellite scene.     

Diacetylene containing polymers

A polyester containing diacetylenic units in main chain was prepared by the polycondensation of m, m-butadiynylene dibenzyl alcohol with terephthaloyl chloride. The polymer was crystalline, and bearly soluble in hot dimethylformamide or dimethylsulfoxide, but insoluble in most organic solvents. It melts at about 200°C. Irradiation of UV light at 75°C gave a reddish brown resin. Heating at temperatures above its melting point gave a shinning black hard solid.     

Water wave diffraction by a small deformation of the ocean bottom for oblique incidence

Summary In this paper, the problem of oblique water wave diffraction by a small deformation of the bottom of a laterally unbounded ocean is considered using linear water wave theory. It is assumed that the fluid is incompressible and inviscid, and the flow irrotational. A perturbation analysis is employed to obtain the velocity potential, reflection and transmission coefficients up to the first order in terms of integrals involving the shape functions c(x) representing the bottom deformation by using Green's integral theorem. Two particular forms of the shape function are considered, and the integrals for the reflection and transmission coefficients are evaluated for these two different functions. Among those cases, for the particular case of a patch of sinusoidal ripples at the bottom, the reflection coefficient up to the first order is found to be an oscillatory function in the quotient of twice the wave number along the x-axis and the ripple wave number. When this quotient becomes one, the theory predicts a resonant interaction between the bed and free surface, and the reflection coefficient becomes a multiple of the number of ripples, and high reflection of the incident wave energy occurs if this number is large. Known results for the normal incidence are recovered as special cases. The numerical solutions for the reflection and transmission coefficients are also evaluated against wave numbers and angles of incidence.