2,597 research outputs found

    Universal schema for entity type prediction

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    Categorizing entities by their types is useful in many applications, including knowledge base construction, relation extraction and query intent prediction. Fine-grained entity type ontologies are especially valuable, but typically difficult to design because of unavoidable quandaries about level of detail and boundary cases. Automatically classifying entities by type is challenging as well, usually involving hand-labeling data and training a supervised predictor. This paper presents a universal schema approach to fine-grained entity type prediction. The set of types is taken as the union of textual surface patterns (e.g. appositives) and pre-defined types from available databases (e.g. Freebase) - yielding not tens or hundreds of types, but more than ten thousands of entity types, such as financier, criminologist, and musical trio. We robustly learn mutual implication among this large union by learning latent vector embeddings from probabilistic matrix factorization, thus avoiding the need for hand-labeled data. Experimental results demonstrate more than 30% reduction in error versus a traditional classification approach on predicting fine-grained entities types. © 2013 ACM

    A cross-border deforestation index to understand underlying drivers of deforestation

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    This paper considers a preliminary investigation involving the development of a Cross-Border Deforestation Index (CBDI), which is an attempt to quantify the differences in deforestation between two countries or potentially any two administrative units. In this study, the focus was on countries. For each pair of bordering countries, a 50km buffer zone was drawn and the average value of the Vegetation Continuous Field (VCF) was calculated for each country in the pair. The ratio of these two averages is the CBDI. Values of 1 indicate similar levels of forest cover but values greater than 1 point towards dissimilar land use policies within countries and/or sub-national administrative levels. This index was calculated for all pairs of bordering tropical countries in South and Central America, Asia and Africa. In addition, a visual analysis of the spatial variation of the VCF was undertaken to show how this can complement the CBDI. The results showed that countries such as Argentina, Brazil, Chile, El Salvador, Laos, Thailand and DR Congo, in combination with different neighbouring countries, all have CBDI values differing from 1. These areas are worth examining in greater detail in order to understand what types of drivers are behind these outlying CBDI values. These drivers could include land use policy, population pressure, accessibility, etc. Future work will i nclude the addition of environmental factors. By computing the CBDI for so called Homogeneous Response Units (HRU: areas of similar or identical environmental conditions in terms of soil, altitude and slope), we will be able to examine the changing effect on the CBDI. This work is still ongoing and will be expanded to consider HRU for all country pairs. In addition, regression of the CBDI with different drivers of deforestation will be attempted in order to help identify these underlying causes

    Optical and electronic properties of sub-surface conducting layers in diamond created by MeV B-implantation at elevated temperatures

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    Boron implantation with in-situ dynamic annealing is used to produce highly conductive sub-surface layers in type IIa (100) diamond plates for the search of a superconducting phase transition. Here we demonstrate that high-fluence MeV ion-implantation, at elevated temperatures avoids graphitization and can be used to achieve doping densities of 6 at.%. In order to quantify the diamond crystal damage associated with implantation Raman spectroscopy was performed, demonstrating high temperature annealing recovers the lattice. Additionally, low-temperature electronic transport measurements show evidence of charge carrier densities close to the metal-insulator-transition. After electronic characterization, secondary ion mass spectrometry was performed to map out the ion profile of the implanted plates. The analysis shows close agreement with the simulated ion-profile assuming scaling factors that take into account an average change in diamond density due to device fabrication. Finally, the data show that boron diffusion is negligible during the high temperature annealing process.Comment: 22 pages, 6 figures, submitted to JA

    An Exploration of Some Pitfalls of Thematic Map Assessment Using the New Map Tools Resource

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    A variety of metrics are commonly employed by map producers and users to assess and compare thematic maps’ quality, but their use and interpretation is inconsistent. This problem is exacerbated by a shortage of tools to allow easy calculation and comparison of metrics from different maps or as a map’s legend is changed. In this paper, we introduce a new website and a collection of R functions to facilitate map assessment. We apply these tools to illustrate some pitfalls of error metrics and point out existing and newly developed solutions to them. Some of these problems have been previously noted, but all of them are under-appreciated and persist in published literature. We show that binary and categorical metrics, including information about true-negative classifications, are inflated for rare categories, and more robust alternatives should be chosen. Most metrics are useful to compare maps only if their legends are identical. We also demonstrate that combining land-cover classes has the often-neglected consequence of apparent improvement, particularly if the combined classes are easily confused (e.g., different forest types). However, we show that the average mutual information (AMI) of a map is relatively robust to combining classes, and reflects the information that is lost in this process; we also introduce a modified AMI metric that credits only correct classifications. Finally, we introduce a method of evaluating statistical differences in the information content of competing maps, and show that this method is an improvement over other methods in more common use. We end with a series of recommendations for the meaningful use of accuracy metrics by map users and producer

    SemEval 2017 Task 10: ScienceIE - Extracting Keyphrases and Relations from Scientific Publications

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    We describe the SemEval task of extracting keyphrases and relations between them from scientific documents, which is crucial for understanding which publications describe which processes, tasks and materials. Although this was a new task, we had a total of 26 submissions across 3 evaluation scenarios. We expect the task and the findings reported in this paper to be relevant for researchers working on understanding scientific content, as well as the broader knowledge base population and information extraction communities

    Digital technologies in support of flood resilience: A case study for Nepal

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    This paper presents ongoing efforts to support flood resilience in the Karnali basin in Nepal through the provision of different forms of digital technology. Flood Risk Geo-Wiki is an online visualization and crowdsourcing tool, which has been adapted to display flood risk maps at the global scale as well as information of relevance to planners and the community at the local level. Community-based flood risk maps, which have traditionally been drawn on paper, are being digitized and integrated with OpenStreetMap to provide better access to this collective knowledge base. Mobile phones, using the GeoODK (Geographical Open Data Kit) questionnaire builder, are being deployed to collect georeferenced information on flood risks and vulnerability, which can be used to validate flood models and design action plans and strategies for coping with future flood events. These types of digital technologies are simple to implement yet together can help support flood prone communities

    Engineering chromium related single photon emitters in single crystal diamond

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    Color centers in diamond as single photon emitters, are leading candidates for future quantum devices due to their room temperature operation and photostability. The recently discovered chromium related centers are particularly attractive since they possess narrow bandwidth emission and a very short lifetime. In this paper we investigate the fabrication methodologies to engineer these centers in monolithic diamond. We show that the emitters can be successfully fabricated by ion implantation of chromium in conjunction with oxygen or sulfur. Furthermore, our results indicate that the background nitrogen concentration is an important parameter, which governs the probability of success to generate these centers.Comment: 14 pages, 5 figure

    S1×S2S^1 \times S^2 wormholes and topological charge

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    I investigate solutions to the Euclidean Einstein-matter field equations with topology S1×S2×RS^1 \times S^2 \times R in a theory with a massless periodic scalar field and electromagnetism. These solutions carry winding number of the periodic scalar as well as magnetic flux. They induce violations of a quasi-topological conservation law which conserves the product of magnetic flux and winding number on the background spacetime. I extend these solutions to a model with stable loops of superconducting cosmic string, and interpret them as contributing to the decay of such loops.Comment: 18 pages (includes 6 figs.), harvmac and epsf, CU-TP-62
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