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Institution

Leibniz University of Hanover

EducationHanover, Niedersachsen, Germany
About: Leibniz University of Hanover is a education organization based out in Hanover, Niedersachsen, Germany. It is known for research contribution in the topics: Finite element method & Population. The organization has 14283 authors who have published 29845 publications receiving 682152 citations.


Papers
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Proceedings ArticleDOI
07 May 2002
TL;DR: In this article, the authors discuss the open source project Edutella which builds upon metadata standards defined for the WWW and aims to provide an RDF-based metadata infrastructure for P2P applications, building on the recently announced JXTA Framework.
Abstract: Metadata for the World Wide Web is important, but metadata for Peer-to-Peer (P2P) networks is absolutely crucial. In this paper we discuss the open source project Edutella which builds upon metadata standards defined for the WWW and aims to provide an RDF-based metadata infrastructure for P2P applications, building on the recently announced JXTA Framework. We describe the goals and main services this infrastructure will provide and the architecture to connect Edutella Peers based on exchange of RDF metadata. As the query service is one of the core services of Edutella, upon which other services are built, we specify in detail the Edutella Common Data Model (ECDM) as basis for the Edutella query exchange language (RDF-QEL-i) and format implementing distributed queries over the Edutella network. Finally, we shortly discuss registration and mediation services, and introduce the prototype and application scenario for our current Edutella aware peers.

939 citations

Journal ArticleDOI
TL;DR: It is shown that an unknown matrix of rank can be efficiently reconstructed from only randomly sampled expansion coefficients with respect to any given matrix basis, which quantifies the “degree of incoherence” between the unknown matrix and the basis.
Abstract: We present novel techniques for analyzing the problem of low-rank matrix recovery. The methods are both considerably simpler and more general than previous approaches. It is shown that an unknown matrix of rank can be efficiently reconstructed from only randomly sampled expansion coefficients with respect to any given matrix basis. The number quantifies the “degree of incoherence” between the unknown matrix and the basis. Existing work concentrated mostly on the problem of “matrix completion” where one aims to recover a low-rank matrix from randomly selected matrix elements. Our result covers this situation as a special case. The proof consists of a series of relatively elementary steps, which stands in contrast to the highly involved methods previously employed to obtain comparable results. In cases where bounds had been known before, our estimates are slightly tighter. We discuss operator bases which are incoherent to all low-rank matrices simultaneously. For these bases, we show that randomly sampled expansion coefficients suffice to recover any low-rank matrix with high probability. The latter bound is tight up to multiplicative constants.

936 citations

Journal ArticleDOI
TL;DR: In this article, the main change drivers for a manufacturing en-terprise can be classified and operationalized, and the evaluation and economic justification of changeability are addressed and a control loop is presented.

934 citations

Journal ArticleDOI
TL;DR: In this article, advances in the strategies for the visible light activation, origin of visible light activity, and electronic structure of various visible-light active TiO 2 photocatalysts are discussed in detail.
Abstract: The remarkable achievement by Fujishima and Honda (1972) in the photo-electrochemical water splitting results in the extensive use of TiO 2 nanomaterials for environmental purification and energy storage/conversion applications. Though there are many advantages for the TiO 2 compared to other semiconductor photocatalysts, its band gap of 3.2 eV restrains application to the UV-region of the electromagnetic spectrum ( λ ≤ 387.5 nm). As a result, development of visible-light active titanium dioxide is one of the key challenges in the field of semiconductor photocatalysis. In this review, advances in the strategies for the visible light activation, origin of visible-light activity, and electronic structure of various visible-light active TiO 2 photocatalysts are discussed in detail. It has also been shown that if appropriate models are used, the theoretical insights can successfully be employed to develop novel catalysts to enhance the photocatalytic performance in the visible region. Recent developments in theory and experiments in visible-light induced water splitting, degradation of environmental pollutants, water and air purification and antibacterial applications are also reviewed. Various strategies to identify appropriate dopants for improved visible-light absorption and electron–hole separation to enhance the photocatalytic activity are discussed in detail, and a number of recommendations are also presented.

921 citations

Journal ArticleDOI
TL;DR: In this paper, the authors studied the ablation of metal targets by Ti:sapphire laser radiation and showed that the intensity depends logarithmically on the laser fluence.
Abstract: Ablation of metal targets by Ti:sapphire laser radiation is studied. The ablation depth per pulse is measured for laser pulse durations between 150 fs and 30 ps and fluences ranging from the ablation threshold ∼0.1 J/cm2 up to 10 J/cm2. Two different ablation regimes are observed for the first time. In both cases the ablation depth per pulse depends logarithmically on the laser fluence. A simple theoretical model for a qualitative description of the experimental results is presented.

914 citations


Authors

Showing all 14621 results

NameH-indexPapersCitations
Hyun-Chul Kim1764076183227
Peter Zoller13473476093
J. R. Smith1341335107641
Chao Zhang127311984711
Benjamin William Allen12480787750
J. F. J. van den Brand12377793070
J. H. Hough11790489697
Hans-Peter Seidel112121351080
Karsten Danzmann11275480032
Bruce D. Hammock111140957401
Benno Willke10950874673
Roman Schnabel10858971938
Jan Harms10844776132
Hartmut Grote10843472781
Ik Siong Heng10742371830
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023221
2022520
20212,280
20202,210
20192,105
20181,959