218 research outputs found
On the location of spectral edges in -periodic media
Periodic nd order ordinary differential operators on are known to
have the edges of their spectra to occur only at the spectra of periodic and
antiperiodic boundary value problems. The multi-dimensional analog of this
property is false, as was shown in a 2007 paper by some of the authors of this
article. However, one sometimes encounters the claims that in the case of a
single periodicity (i.e., with respect to the lattice ), the
property still holds, and spectral edges occur at the periodic and
anti-periodic spectra only. In this work we show that even in the simplest case
of quantum graphs this is not true. It is shown that this is true if the graph
consists of a chain of finite graphs connected by single edges, while if
the connections are formed by at least two edges, the spectral edges can
already occur away from the periodic and anti-periodic spectra.Comment: 9 pages, 5 figure
KOSHIK: A large-scale distributed computing framework for NLP
In this paper, we describe KOSHIK, an end-to-end framework to process the unstructured natural language content of multilingual documents. We used the Hadoop distributed computing infrastructure to build this framework as it enables KOSHIK to easily scale by adding inexpensive commodity hardware. We designed an annotation model that allows the processing algorithms to incrementally add layers of annotation without modifyingtheoriginaldocument. We used the Avro binary format to serialize th edocuments. Avro is designed for Hadoop and allows other data warehousing tools to directly query the documents. This paper reports the implementation choices and details of the framework,the annotation model,the options for querying processed data, and the parsing results on the English and Swedish editions of Wikipedia
Using Syntactic Dependencies to Solve Coreferences
This paper describes the structure of the LTH coreference solver used in the closed track of the CoNLL 2012 shared task (Pradhan et al., 2012). The solver core is a mention classifier that uses Soon et al. (2001)âs algorithm and features extracted from the dependency graphs of the sentences. This system builds on Björkelund and Nugues (2011)âs solver that we extended so that it can be applied to the three languages of the task: English, Chinese, and Arabic. We designed a new mention detection module that removes pleonastic pronouns, prunes constituents, and recovers mentions when they do not match exactly a noun phrase. We carefully redesigned the features so that they reflect more complex linguistic phenomena as well as discourse properties. Finally, we introduced a minimal cluster model grounded in the first mention of an entity. We optimized the feature sets for the three languages: We carried out an extensive evaluation of pairs of features and we complemented the single features with associations that improved the CoNLL score. We obtained the respective scores of 59.57, 56.62, and 48.25 on English, Chinese, and Arabic on the development set, 59.36, 56.85, and 49.43 on the test set, and the combined official score of 55.21.
On the location of spectral edges in Z-periodic media
Periodic second-order ordinary differential operators on R are known to have
the edges of their spectra to occur only at the spectra of periodic and antiperiodic
boundary value problems. The multi-dimensional analog of this
property is false, as was shown in a 2007 paper by some of the authors of
this paper. However, one sometimes encounters the claims that in the case of
a single periodicity (i.e., with respect to the lattice Z), the 1D property still
holds, and spectral edges occur at the periodic and anti-periodic spectra only.
In this work, we show that even in the simplest case of quantum graphs this is
not true. It is shown that this is true if the graph consists of a 1D chain of finite
graphs connected by single edges, while if the connections are formed by at
least two edges, the spectral edges can already occur away from the periodic
and anti-periodic spectra
SensorMapRT â a System for Real-Time Acquisition, Visualization and Analysis of Mobile Sensor Data in an Urban Context
The use of wearables in citizensâ daily life will increase significantly in the coming years. By analyzing these sensor data, it is possible to detect the emotional well-being in urban areas, which is highly relevant for urban planning purposes. Through the combination of several physiological and other sensor data such as GPS, "stress spots" in the urban environment can be recognized and located. A major objective of this project is therefore, to combine and evaluate various research approaches in the field of human as sensorswith wearables. This is the reason why the project group will be an interdisciplinary cooperation between spatial planning, psychophysiology and computer technology.Together with the project partner cities of Neustadt an der WeinstraĂe and Pirmasens in the German Federal State Rhineland-Palatine, the project group aims to show exemplary the influence of potential stressing factors in the urban area such as traffic and noise and creates scientifically-robust models of stress detection in urban areas. Besides this, a visualization for planning purposes with the tool GeoVisualizer as well as an evaluation of the resilience of such informtion and their potential use for urban planning is aim of the project
Combining Text Semantics and Image Geometry to Improve Scene Interpretation
Inthispaper,wedescribeanovelsystemthatidentiïŹesrelationsbetweentheobjectsextractedfromanimage. We started from the idea that in addition to the geometric and visual properties of the image objects, we could exploit lexical and semantic information from the text accompanying the image. As experimental set up, we gathered a corpus of images from Wikipedia as well as their associated articles. We extracted two types of objects: human beings and horses and we considered three relations that could hold between them: Ride, Lead, or None. We used geometric features as a baseline to identify the relations between the entities and we describe the improvements brought by the addition of bag-of-wordf eatures and predicateâarguments tructures we derived from the text. The best semantic model resulted in a relative error reduction of more than 18% over the baseline
The seasonal dynamics of the stream sources and input flow paths of water and nitrogen of an Austrian headwater agricultural catchment
AbstractOur study examines the source aquifers and stream inputs of the seasonal water and nitrogen dynamics of a headwater agricultural catchment to determine the dominant driving forces for the seasonal dynamics in the surface water nitrogen loads and concentrations. We found that the alternating aquifer contributions throughout the year of the deep and shallow aquifers were the main cause for the seasonality of the nitrate concentration. The deep aquifer water typically contributed 75% of the total outlet discharge in the summer and 50% in the winter when the shallow aquifer recharges due to low crop evapotranspiration. The shallow aquifer supplied the vast majority of the nitrogen load to the stream due to the significantly higher total nitrogen concentration (11mg-N/l) compared to the deep aquifer (0.50mg-N/l). The main stream input pathway for the shallow aquifer nitrogen load was from the perennial tile drainages providing 60% of the total load to the stream outlet, while only providing 26% of the total flow volume. The diffuse groundwater input to the stream was the largest input to the stream (39%), but only supplied 27% to the total nitrogen load as the diffuse water was mostly composed of deep aquifer water
Urban Emotions â Tools of Integrating Peopleâs Perception into Urban Planning
This paper introduces the research field âUrban Emotionsâ â an interdisciplinary approach combining not only spatial planning and (geo-) informatics, but also computer linguistics and sensor technology methods. A new set of methods will be formed for the area of urban and spatial planning, resulting in a fundamental change of the understanding of planning. One of the main objectives is the involvement of citizens into planning processes. Therefore, new techniques are developed to collect and analyse data on the emotional perception of space and provide it to the people and also planners. Not only the human perception in the context of the city, and the combination with human sensory processes are contents of this paper, but also the critical discussion of these effects to privacy issues. Based on the topics âmental mapsâ and psychogeography in combination with the field of digital emotional urban tagging, the potential of integrating objectively quantified emotions in the context of citizen participation will be explained. In the following, partly established and partly experimental methods for collecting and analysing âUrban Emotionsâ will be introduced. Based on two studies, the possibilities of transfering these methodsinto the planning praxis will be shown on the one hand and on the other hand the potential for further development for other disciplines will be more evident
Taurine-Modified Boehmite Nanoparticles for GFRP Wind Turbine Rotor Blade Fatigue Life Enhancement
Advanced nanoparticle-reinforced glass fibre composites represent a promising approach to improving the service life of fatigue-loaded structures such as wind turbine rotor blades. However, processing particle-reinforced resins using advanced infusion techniques is problematic due to, for example, higher viscosity as well as filtering effects. In this work, the effects of boehmite nanoparticles on viscosity, static properties and fatigue life are investigated experimentally. Whereas rheological analysis reveals a significant increase of viscosity in the case of pristine boehmite particles, an additional taurine surface modification of the particles can effectively reduce viscosity increase. As regards mechanical properties, significant improvements of both static as well as fatigue properties are found. The addition of 15 wt.% of boehmite particles increases fatigue life by a maximum of 270% compared to the unmodified fibre-reinforced epoxy. Transmitted light-based investigation of the damage mechanisms shows delayed initiation and smaller growth rates for laminates containing boehmite particles. At the same time, the observed mechanisms and their accumulation along the relative cycle number do not change significantly. In addition, by characterising autonomous heating, the so-called Risitano fatigue limit is determined. The results reveal that with increasing particle content there is an increase in the fatigue limit
- âŠ