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Search Results: 1 - 10 of 29291 matches for " Rolf Robert "
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Two Years after the Fourth External Review: TDR Moves Forward with a New Vision and Strategy
Robert G. Ridley ,Peter Ndumbe,Rolf Korte
PLOS Neglected Tropical Diseases , 2008, DOI: 10.1371/journal.pntd.0000307
Pattern-Guided k-Anonymity
Robert Bredereck,André Nichterlein,Rolf Niedermeier
Algorithms , 2013, DOI: 10.3390/a6040678
Abstract: We suggest a user-oriented approach to combinatorial data anonymization. A data matrix is called k-anonymous if every row appears at least k times—the goal of the NP-hard k-ANONYMITY problem then is to make a given matrix k-anonymous by suppressing (blanking out) as few entries as possible. Building on previous work and coping with corresponding deficiencies, we describe an enhanced k-anonymization problem called PATTERN-GUIDED k-ANONYMITY, where the users specify in which combinations suppressions may occur. In this way, the user of the anonymized data can express the differing importance of various data features. We show that PATTERN-GUIDED k-ANONYMITY is NP-hard. We complement this by a fixed-parameter tractability result based on a “data-driven parameterization” and, based on this, develop an exact integer linear program (ILP)-based solution method, as well as a simple, but very effective, greedy heuristic. Experiments on several real-world datasets show that our heuristic easily matches up to the established “Mondrian” algorithm for k-ANONYMITY in terms of the quality of the anonymization and outperforms it in terms of running time.
Open source software development for neuroinformatics
Rolf K. K?tter,Robert C. Cannon
Frontiers in Neuroinformatics , 2008, DOI: 10.3389/neuro.11.008.2007
Synthesis of Reversible Functions Beyond Gate Count and Quantum Cost
Robert Wille,Mehdi Saeedi,Rolf Drechsler
Physics , 2010,
Abstract: Many synthesis approaches for reversible and quantum logic have been proposed so far. However, most of them generate circuits with respect to simple metrics, i.e. gate count or quantum cost. On the other hand, to physically realize reversible and quantum hardware, additional constraints exist. In this paper, we describe cost metrics beyond gate count and quantum cost that should be considered while synthesizing reversible and quantum logic for the respective target technologies. We show that the evaluation of a synthesis approach may differ if additional costs are applied. In addition, a new cost metric, namely Nearest Neighbor Cost (NNC) which is imposed by realistic physical quantum architectures, is considered in detail. We discuss how existing synthesis flows can be extended to generate optimal circuits with respect to NNC while still keeping the quantum cost small.
Parareal for diffusion problems with space- and time-dependent coefficients
Daniel Ruprecht,Robert Speck,Rolf Krause
Mathematics , 2014,
Abstract: For the time-parallel Parareal method, there exists both numerical and analytical proof that it converges very well for diffusive problems like the heat equation. Many applications, however, do not lead to simple homogeneous diffusive scenarios but feature strongly inhomogeneous and possibly anisotropic coefficients. The paper presents results from a numerical study of how space- and time-dependent coefficients in a diffusion setup affect Parareal's convergence behaviour. It is shown that, for the presented examples, non-constant diffusion coefficients have only marginal influence on how fast Parareal converges. Furthermore, an example is shown that illustrates how for linear problems the maximum singular value of the Parareal iteration matrix can be used to estimate convergence rates.
Synthesis of Quantum Circuits for Linear Nearest Neighbor Architectures
Mehdi Saeedi,Robert Wille,Rolf Drechsler
Computer Science , 2011, DOI: 10.1007/s11128-010-0201-2
Abstract: While a couple of impressive quantum technologies have been proposed, they have several intrinsic limitations which must be considered by circuit designers to produce realizable circuits. Limited interaction distance between gate qubits is one of the most common limitations. In this paper, we suggest extensions of the existing synthesis flow aimed to realize circuits for quantum architectures with linear nearest neighbor (LNN) interaction. To this end, a template matching optimization, an exact synthesis approach, and two reordering strategies are introduced. The proposed methods are combined as an integrated synthesis flow. Experiments show that by using the suggested flow, quantum cost can be improved by more than 50% on average.
Digital Sport-Management Games and Their Contribution to Prospective Sport-Managers’ Competence Development  [PDF]
Rolf Kretschmann
Advances in Physical Education (APE) , 2012, DOI: 10.4236/ape.2012.24031
Abstract: The immersive and engaging characteristics of digital games are leading current pedagogical discussions about digital media. Game scientists, (pedagogical) researches, and practitioners continue to attempt to embed digital games in pedagogical settings. They consider these games to be so called serious games. The idea of serious games is that a digital game is not only played for fun and entertainment, but to employ the specific game-play for serious learning processes and outcomes in a specific field of learning or work. Hence, the question arises, whether a digital sport-management game can assist prospective sport managers and students of sport management at the introduction to this complex field of work. To tackle the research question, it is necessary to investigate the profession of sport managers in “real” life and compare the game-play of a digital sport management game to them. Therefore, the best selling and most famous so-called commercial off-the-shelf (COTS) game FIFA Manager 09 by EA Sports is picked to be the subject of analysis. “Virtual” sport-manager competencies were compared to “real-world” sport- manager competencies to find any matching. As a result, there actually is a high congruence between sport- management competence-models and the digital game’s game-play.
Caerulein-induced acute pancreatitis in mice that constitutively overexpress Reg/PAP genes
Oxana Norkina, Rolf Graf, Philippe Appenzeller, Robert C De Lisle
BMC Gastroenterology , 2006, DOI: 10.1186/1471-230x-6-16
Abstract: To test this idea the supramaximal caerulein model was used to induce acute pancreatitis in wild type and CF mice. Serum amylase, pancreatic water content (as a measure of edema), pancreatic myeloperoxidase activity, and Reg/PAP expression were quantified.In both wild type and CF mice caerulein induced similar elevations in serum amylase (maximal at 12 h), pancreatic edema (maximal at 7 h), and pancreatic myeloperoxidase activity (MPO, a marker of neutrophil infiltration; maximal at 7 h). By immunohistochemistry, Reg3α was strongly expressed in the untreated CF pancreas but not in wild type. During pancreatitis, Reg3α was intensely expressed in foci of inflamed tissue in both wild type and CF.These data demonstrate that the severity of caerulein-induced pancreatitis is not ameliorated in the CF mouse even though the Reg/PAP stress genes are already highly upregulated. While Reg/PAP may be protective they may also have a negative effect during pancreatitis due to their anti-apoptotic activity, which has been shown to increase the severity of pancreatitis.There is a strong association of the Reg/PAP genes with pancreatic stress and injury, especially in response to pancreatitis [1,2]. The role of these proteins has been investigated under various conditions. PAP appears to have an anti-inflammatory effect in pancreatic injury [3] as well as in inflammatory bowel disease [4]. In vitro experiments demonstrated that PAP can inhibit TNF-α mediated inflammatory responses of macrophages [3] and of epithelial and endothelial cells [4]. Experimental evidence also suggests that Reg/PAP are mitogenic and/or anti-apoptotic and enhance cell survival during development and in injured tissues [5-7]. The anti-apoptotic activity of Reg/PAP is of interest to pancreatitis, as experimental evidence shows that reduction of apoptosis can be associated with a worsened severity of pancreatitis [8,9].The Reg/PAP proteins are synthesized in a soluble form that, upon tryptic cleavage of an 11
Set-base dynamical parameter estimation and model invalidation for biochemical reaction networks
Philipp Rumschinski, Steffen Borchers, Sandro Bosio, Robert Weismantel, Rolf Findeisen
BMC Systems Biology , 2010, DOI: 10.1186/1752-0509-4-69
Abstract: In this work we present a set-based framework that allows to discriminate between competing model hypotheses and to provide guaranteed outer estimates on the model parameters that are consistent with the (possibly sparse and uncertain) experimental measurements. This is obtained by means of exact proofs of model invalidity that exploit the polynomial/rational structure of biochemical reaction networks, and by making use of an efficient strategy to balance solution accuracy and computational effort.The practicability of our approach is illustrated with two case studies. The first study shows that our approach allows to conclusively rule out wrong model hypotheses. The second study focuses on parameter estimation, and shows that the proposed method allows to evaluate the global influence of measurement sparsity, uncertainty, and prior knowledge on the parameter estimates. This can help in designing further experiments leading to improved parameter estimates.Mathematical modeling has become an important tool for analysis and prediction of metabolic and signal transduction processes [1,2]. Given a biological system and some experimental evidence, deriving a model hypothesis that captures the essential behavior of the system under study is a nontrivial task. Limited prior knowledge on the involved reaction mechanisms and signaling pathways may lead to competing structural hypotheses, whose parameters might be completely or largely unknown. Moreover, the model dynamics are typically strongly influenced by the model parameters [3,4]. An accurate parameter estimation is thus a crucial step to conclusively discriminate between structural alternatives, allowing to discard models for which it can be proved that no parametrization is consistent with the experimental evidence.Model invalidation and parameter estimation are considerably more challenging in biology than in other experimental and engineering sciences, requiring specifically tailored methods. Experiments are usually
The Hip Fracture Surgery in Elderly Patients (HIPELD) study: protocol for a randomized, multicenter controlled trial evaluating the effect of xenon on postoperative delirium in older patients undergoing hip fracture surgery
Coburn Mark,Sanders Robert D,Maze Mervyn,Rossaint Rolf
Trials , 2012, DOI: 10.1186/1745-6215-13-180
Abstract: Background Strategies to protect the brain from postoperative delirium (POD) after hip fracture are urgently needed. The development of delirium often is associated with the loss of independence, poor functional recovery, and increased morbidity, as well as increases in length of hospital stay, discharges to nursing facilities, and healthcare costs. We hypothesize that xenon may reduce the burden of POD, (i) by avoiding the need to provide anesthesia with a drug that targets the γ-amino-butyric acid (GABA)A receptor and (ii) through beneficial anesthetic and organ-protective effects. Methods and design An international, multicenter, phase 2, prospective, randomized, blinded, parallel group and controlled trial to evaluate the incidence of POD, diagnosed with the Confusion Assessment Method (CAM), in older patients undergoing hip fracture surgery under general anesthesia with xenon or sevoflurane, for a period of 4 days post surgery (primary outcome) is planned. Secondary objectives are to compare the incidence of POD between xenon and sevoflurane, to evaluate the incidence of POD from day 5 post surgery until discharge from hospital, to determine the time to first POD diagnosis, to evaluate the duration of POD, to evaluate the evolution of the physiological status of the patients in the postoperative period, to evaluate the recovery parameters, to collect preliminary data to evaluate the economical impact of POD in the postoperative period and to collect safety data. Patients are eligible if they are older aged (≥ 75 years) and assigned to a planned hip fracture surgery within 48 h after the hip fracture. Furthermore, patients need to be willing and able to complete the requirements of this study including the signature of the written informed consent. A total of 256 randomized patients in the 10 participating centers will be recruited, that is, 128 randomized patients in each of the 2 study groups (receiving either xenon or sevoflurane). Trial registration EudraCT Identifier: 2009-017153-35; ClinicalTrials.gov Identifier: NCT01199276
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