A. H. C. Thean

Leibniz Institute for the German Language

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Co-Authors

A. Pedlar

University of Manchester

Marcel Worring

University of Amsterdam

Lynn Meijerman

Leiden University Medical Center

G. J. R. Maat

Leiden University Medical Center

Cees G. M. Snoek

University of Amsterdam

A.W.M. Smeulders

University of Amsterdam

M. J. Kukula

Royal Observatory in Greenwich

Ork de Rooij

University of Amsterdam

Elena Ranguelova

Netherlands eScience Center

D.C. Koelma

University of Amsterdam

Cooperative Institutions

University of Amsterdam

Netherlands Organisation for Applied Scientific Research

University of Manchester

SKA Observatory

Idiap Research Institute

Amsterdam University of the Arts

Amsterdam University of Applied Sciences

Delft University of Technology

École Polytechnique Fédérale de Lausanne

Vrije Universiteit Amsterdam

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Visual Tools for Assisting Child Pornography Investigators

Pieter T. Eendebak Wessel Kraaij Stephan Raaijmakers Elena Ranguelova Ork de Rooij

In this paper we investigate the use of visual tools for efficient video search. The different techniques have been implemented in a demo called iDash and several of the techniques are actively used by the Dutch police force in the fight against child pornography.

Child pornography

Pornography

Visual methods

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Citations (2)

Earprints in Forensic Investigations

Forensic Science Medicine and Pathology (2005)

Lynn Meijerman A. H. C. Thean G. J. R. Maat

Variation (astronomy)

Section (typography)

10.1385/fsmp:1:4:247

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Citations (21)

Earprints

CRC Press eBooks (2006)

Cornelis Van Der Lugt A. H. C. Thean Lynn Meijerman G. J. R. Maat

10.1201/9781420005714.ch4

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Citations (0)

Mediamill: Searching Multimedia Archives Based on Learned Semantics

Cees G. M. Snoek D.C. Koelma Jeroen van Rest N. Schipper F.J. Seinstra

Video is about to conquer the Internet. Real-time delivery of video content is technically possible to any desktop and mobile device, even with modest connections. The main problem hampering massive (re)usage of video content today is the lack of effective content-based tools that provide semantic access. In this contribution, we discuss systems for both video analysis and video retrieval that facilitate semantic access to video sources. Both systems were evaluated in the 2004 TRECVID benchmark as top performers in their task

Video retrieval

Benchmark (surveying)

Interactive video

10.1109/icme.2005.1521736

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Linear radio structures in selected Seyfert galaxies

Monthly Notices of the Royal Astronomical Society (2010)

E. Xanthopoulos A. H. C. Thean A. Pedlar A. M. S. Richards

High-resolution Multi-Element Radio Linked Interferometer Network 5-GHz observations of seven Seyfert galaxies, selected as the ones previously showing evidence of collimated ejection, have been compared with high-resolution Hubble Space Telescope data. A radio and optical/near-ultraviolet emission correlation is apparent in all the sources. The radio maps reveal rich structures in the entire sample. NGC 2639 and TXFS 2226−184 have multiple-knot parsec-scale extended structures, Mrk 1034NED02, Mrk 1210, NGC 4922NED02 and NGC 5506 reveal one-sided jets, while IC 1481 exhibits jet features. Interaction between these very small (mostly mas) sub-kpc jets with dense material gives rise to symptoms of a disrupted medium, signatures of which are present in all the sources.

Collimated light

Very-long-baseline interferometry

Hubble sequence

10.1111/j.1365-2966.2010.16416.x

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Citations (12)

EVN observations of low-luminosity flat-spectrum active galactic nuclei

Monthly Notices of the Royal Astronomical Society (2001)

A. Caccianiga M. J. M. Marchã A. H. C. Thean J. Dennett-Thorpe

We present and discuss the results of very-long baseline interferometry (VLBI, EVN) observations of three low-luminosity broad emission line active galactic nuclei (AGNs) carefully selected from a sample of flat-spectrum radio sources (CLASS). Based on the total and the extended radio power at 5 and at 1.4 GHz respectively, these objects should be technically classified as radio-quiet AGN and thus the origin of their radio emission is not clearly understood. The VLBI observations presented in this paper have revealed compact radio cores which imply a lower limit on the brightness temperature of about . This result rules out a thermal origin for the radio emission and strongly suggests an emission mechanism similar to that observed in more powerful radio-loud AGNs. Since, by definition, the three objects show a flat (or inverted) radio spectrum between 1.4 and 8.4 GHz, the observed radio emission could be relativistically beamed. Multi-epoch VLBI observations can confirm this possibility in two years’ time.

Very-long-baseline interferometry

Radio spectrum

10.1046/j.1365-8711.2001.04928.x

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Citations (15)

Earprints: Interpretation of

Wiley Encyclopedia of Forensic Science (2009)

Lynn Meijerman A. H. C. Thean G. J. R. Maat

Abstract We aim at providing an overview of the theoretical and practical issues concerning the use of earprints in forensic research. A limited account of the history of earprints in forensic investigations and their use as evidence in the court is provided. Criticism of the use of earprints for individualization is addressed and fundamental questions that require further attention are summarized. Approaches to automatic classification and matching are discussed. Finally, we summarize the results of various studies that we have performed on earprint variation.

Variation (astronomy)

10.1002/9780470061589.fsa132

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Citations (3)

Interactive search using a lexicon too large to remember (slides)

Marcel Worring Bouke Huurnink Ork de Rooij Cees G. M. Snoek A. H. C. Thean

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Collaborative Visual-servoing of the MANUS Manipulator

Springer eBooks (2006)

Freek Liefhebber Bart Driessen A. H. C. Thean

Manus

Visual Servoing

Manipulator (device)

10.1007/1-84628-365-5_12

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Citations (1)

High-resolution radio observations of Seyfert galaxies in the extended 12- m sample - II. The properties of compact radio components

Monthly Notices of the Royal Astronomical Society (2001)

A. H. C. Thean A. Pedlar M. J. Kukula S. A. Baum C. P. O’Dea

We discuss the properties of compact nuclear radio components in Seyfert galaxies from the extended 12-μm AGN sample of Rush et al. Our main results can be summarized as follows. Type 1 and type 2 Seyferts produce compact radio components which are indistinguishable in strength and aspect, indicating that their central engines are alike, as proposed by the unification model. Infrared IRAS fluxes are more closely correlated with low-resolution radio fluxes than high-resolution radio fluxes, suggesting that they are dominated by kiloparsec-scale, extranuclear emission regions; extranuclear emission may be stronger in type 2 Seyferts. Early-type Seyfert galaxies tend to have stronger nuclear radio emission than late-type Seyfert galaxies. V-shaped extended emission-line regions, indicative of 'ionization cones', are usually found in sources with large, collimated radio outflows. Hidden broad lines are most likely to be found in sources with powerful nuclear radio sources. Type 1 and type 2 Seyferts selected by their IRAS 12-μm flux densities have well-matched properties.

Sample (material)

X-shaped radio galaxy

Galactic nuclei

10.1046/j.1365-8711.2001.04485.x

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Citations (43)