795 research outputs found

    Modelling decision tables from data.

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    On most datasets induction algorithms can generate very accurate classifiers. Sometimes, however, these classifiers are very hard to understand for humans. Therefore, in this paper it is investigated how we can present the extracted knowledge to the user by means of decision tables. Decision tables are very easy to understand. Furthermore, decision tables provide interesting facilities to check the extracted knowledge on consistency and completeness. In this paper, it is demonstrated how a consistent and complete DT can be modelled starting from raw data. The proposed method is empirically validated on several benchmarking datasets. It is shown that the modelling decision tables are sufficiently small. This allows easy consultation of the represented knowledge.Data;

    Photocathodes for a post-processed imaging array

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    Preliminary results of a photon detector combining a Micromegas like multiplier coated with a UV-sensitive CsI photocathode are described. The multiplier is made in the CMOS compatible InGrid technology, which allows to post-process it directly on the surface of an imaging IC. This method is aimed at building light-sensitive imaging detectors where all elements are monolithically integrated. We show that the CsI photocathode deposited in the InGrid mesh does not alter the device performance. Maximum gains of ~6000 were reached in a singlegrid element operated in Ar/CH4, with a 2% Ion Back Flow fraction returning to the photocathode

    A Radiation Imaging Detector Made by Postprocessing a Standard CMOS Chip

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    An unpackaged microchip is used as the sensing element in a miniaturized gaseous proportional chamber. Thisletter reports on the fabrication and performance of a complete radiation imaging detector based on this principle. Our fabrication schemes are based on wafer-scale and chip-scale postprocessing.\ud Compared to hybrid-assembled gaseous detectors, our microsystem shows superior alignment precision and energy resolution, and offers the capability to unambiguously reconstruct 3-D radiation tracks on the spot.\u

    Empirical Methodology for Crowdsourcing Ground Truth

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    The process of gathering ground truth data through human annotation is a major bottleneck in the use of information extraction methods for populating the Semantic Web. Crowdsourcing-based approaches are gaining popularity in the attempt to solve the issues related to volume of data and lack of annotators. Typically these practices use inter-annotator agreement as a measure of quality. However, in many domains, such as event detection, there is ambiguity in the data, as well as a multitude of perspectives of the information examples. We present an empirically derived methodology for efficiently gathering of ground truth data in a diverse set of use cases covering a variety of domains and annotation tasks. Central to our approach is the use of CrowdTruth metrics that capture inter-annotator disagreement. We show that measuring disagreement is essential for acquiring a high quality ground truth. We achieve this by comparing the quality of the data aggregated with CrowdTruth metrics with majority vote, over a set of diverse crowdsourcing tasks: Medical Relation Extraction, Twitter Event Identification, News Event Extraction and Sound Interpretation. We also show that an increased number of crowd workers leads to growth and stabilization in the quality of annotations, going against the usual practice of employing a small number of annotators.Comment: in publication at the Semantic Web Journa

    Casual Sexual Scripts on the Screen

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    While existing content analyses have provided insightful information in terms of contextual factors and frequency of sexual behaviors, not much is known about the relational context in which sexual depictions generally occur. The current study addresses this void by employing content analytic methods to measure the frequency and context o

    Minder en Anders Bemesten; resultaten van een vierjarig project over innovatieve bemesting.

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    In this report a summary is given from several experiments during three years at four farms. This summary focuses on yield; mineral balances and product quality are sometimes described. The overall soil quality descriptions can only be found in the complete reports which can be found in the reference list. This project aimed at reduced manure applications in an adapted fertilization strategy in several farm types, realizing: • Equal or higher yields • Improvement of product quality • Maintenance or improvement of sustainable soil fertility. The results of the experiments at four farms are: • At Joost van Strien’s farm it has been shown clear that the use of cut-and-carry fertilizers is a good option. The fertilizing value is as good as or better than manure, and the mineral content (N. P. K) is more in accordance with crop uptake than in case of manure. Next step to assess is the consequence at farm level when striving towards 100% own nitrogen supply by means of cut-and-carry fertilizers. • At Jan en Hans Rozendaal’s farm the need for manure in the courgette crop is reduced by introducing grassclover as pre-crop. The nitrogen release out of this pre-crop is a bit delayed, so in the beginning of the season some additional fast-acting nitrogen fertilizer is still needed. This system, with the crop on small beds, has shown to work for courgettes but not for cabbage. • At Jan van Lierop’s farm the two components of nitrogen dynamics have been explored: long term nitrogen release by means of soil organic matter, short term by means of specific fertilizer applications. A good mix of these two components is needed, but this is possibly not enough to cope the nutrient balance challenges. More changes might be needed such as choice of manure, introduction of catch crops and a less intensive production system. • At Gerard Lanting’s farm the experiments have shown that in case of a sufficient basic soil fertility the additionally requested manure is lower than what is recommended normally. In a scenario study with changes in crops and manure strategy it is shown that a reduced manure input can be realized without yield reduction At the end of this report a list of conclusions is given, showing that there is a wide range of means needed and possible to create a substantial increase in nutrient use efficiency

    Thermo-mechanical analysis of flexible and stretchable systems

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    This paper presents a summary of the modeling and technology developed for flexible and stretchable electronics. The integration of ultra thin dies at package level, with thickness in the range of 20 to 30 μ m, into flexible and/or stretchable materials are demonstrated as well as the design and reliability test of stretchable metal interconnections at board level are analyzed by both experiments and finite element modeling. These technologies can achieve mechanically bendable and stretchable subsystems. The base substrate used for the fabrication of flexible circuits is a uniform polyimide layer, while silicones materials are preferred for the stretchable circuits. The method developed for chip embedding and interconnections is named Ultra Thin Chip Package (UTCP). Extensions of this technology can be achieved by stacking and embedding thin dies in polyimide, providing large benefits in electrical performance and still allowing some mechanical flexibility. These flexible circuits can be converted into stretchable circuits by replacing the relatively rigid polyimide by a soft and elastic silicone material. We have shown through finite element modeling and experimental validation that an appropriate thermo mechanical design is necessary to achieve mechanically reliable circuits and thermally optimized packages

    Beam Test with a GridGEM TPC Prototype Module

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    The International Large Detector (ILD) --a detector concept for the International Linear Collider (ILC)-- foresees a Time Projection Chamber (TPC) as its main tracking detector. Currently, the R&D efforts for such a TPC focus on studies using a large prototype that can accommodate up to seven read-out modules which are comparable to the ones that would be used in the final ILD TPC. The DESY TPC group has developed such a module using GEMs for the gas amplification, which are mounted on thin ceramic frames. The module design and first results of a test beam campaign are presented.Comment: 6 pages, 11 figures, prepared for LCWS 2011 proceeding

    Dysregulation of microtubule stability impairs morphofunctional connectivity in primary neuronal networks

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    Functionally related neurons assemble into connected networks that process and transmit electrochemical information. To do this in a coordinated manner, the number and strength of synaptic connections is tightly regulated. Synapse function relies on the microtubule (MT) cytoskeleton, the dynamics of which are in turn controlled by a plethora of MT-associated proteins, including the MT-stabilizing protein Tau. Although mutations in the Tau-encodingMAPT gene underlie a set of neurodegenerative disorders, termed tauopathies, the exact contribution of MT dynamics and the perturbation thereof to neuronal network connectivity has not yet been scrutinized. Therefore, we investigated the impact of targeted perturbations of MT stability on morphological (e.g., neurite- and synapse density) and functional (e.g., synchronous calcium bursting) correlates of connectivity in networks of primary hippocampal neurons. We found that treatment with MT-stabilizing or -destabilizing compounds impaired morphofunctional connectivity in a reversible manner. We also discovered that overexpression of MAPT induced significant connectivity defects, which were accompanied by alterations in MT dynamics and increased resistance to pharmacological MT depolymerization. Overexpression of a MAPT variant harboring the P301L point mutation in the MT-binding domain did far less, directly linking neuronal connectivity with Tau's MT binding affinity. Our results show that MT stability is a vulnerable node in tauopathies and that its precise pharmacological tuning may positively affect neuronal network connectivity. However, a critical balance in MT turnover causes it to be a difficult therapeutic target with a narrow operating window

    Minder en Anders Bemesten. Onderzoeksresultaten tuinbouw op klei. Rozendaal, courgette 2009

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    In het kader van het project Minder en Anders Bemesten is op het bedrijf van Jan en Hans van Lierop vervolgonderzoek uitgevoerd. In een veldexperiment in herhalingen is getracht de productie van courgette gelijkmatiger in het seizoen te verdelen door op twee peilers te steunen: een bescheiden bemesting om de productie in het begin van het seizoen te verhogen, en grasklaver als voorvrucht om de productie verderop in het seizoen te verhogen. De resultaten tonen dat deze aanpak werkt: met een relatief kleine bemesting is er geen sprake van een verlaagde opbrengst in de eerste helft van de productieperiode. Verder is de bodemstructuur verbeterd door de grasklaver en is de mestgift lager dan anders het geval zou zijn geweest
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