1,490 research outputs found
Intracerebroventricular administration of creatine protects against damage by global cerebral ischemia in rat
No full textHandleiding benchmark VO
No full textOnderzoeksrapportenArchiefTechniek, Bestuur en Management> Over faculteit> Afdelingen> Innovation Systems> IPSE> Onderzoek> Publicaties> Onderzoeksrapporten> Handleiding benchmark VO Handleiding benchmark VO 25 november 2008 door IPSE Studies Door J.L.T. Blank. Handleiding voor het lezen van de individuele benchmarks voor scholen. Dit is een uitvloeisel van de onderzoeksopdracht van de VO-raad naar bureaucratie in het voortgezet onderwijs. In de individuele schoolrapportages staan verschillende kengetallen van een school afgezet tegen die van andere scholen. Kengetallen hebben betrekking op kosten, prestaties, bureaucratie en doelmatigheid
Thu Vo Phien (Vo Phien's Letters) [In Vietnamese]
No full textVO PHIEN'S LETTERS In this book (384 pages), I write about Vo Phien's letters. In Western countries, collections of letters written by famous writers are fairly common. This has a long tradition which can be traced back more than two thousand years to ancient Greek literature. In Vietnam the situation is different: This is the first collection of letters written by a Vietnamese author which has been published. Vo Phien's letters are not only beautifully written but also reveal his colorful life and his deep thoughts on literature and art. It is useful for critics and literary historians who want to study modern Vietnamese literature, particularly, literature in exile
Using VO Concept for Managing Dynamic Security Associations
No full textThis chapter discusses how the Virtual Organisation (VO) concept can be used for managing dynamic security associations in collaborative applications and for complex resource provisioning as possible components of the Agent based Virtual Enterprises. The chapter provides an overview of the current practice in VO management at the organisational level and its support at the security middleware level. It identifies open issues and basic requirements to the VO security functionality and services and suggests possible directions of further research and development, in particular, VO management concept, VO security services operation, and basic VO operational models. The author hopes that understanding the VO concept and current practice in Grid of using VO for managing security associations will help developers effectively use Gird technologies and middleware for building distributed security infrastructure for Virtual Enterprises.</jats:p
An improved quasi-reversibility method for a terminal-boundary value multi-species model with white Gaussian noise
No full textUpon the recent development of the quasi-reversibility method for terminal value parabolic problems in Nguyen et al. (2019), it is imperative to investigate the convergence analysis of this regularization method in the stochastic setting. In this paper, we positively unravel this open question by focusing on a coupled system of Dirichlet reaction-diffusion equations with additive white Gaussian noise on the terminal data. In this regard, the approximate problem is designed by adding the so-called perturbing operator to the original problem and by exploiting the Fourier reconstructed terminal data. By this way, Gevrey-type source conditions are included, while we successfully maintain the logarithmic stability estimate of the corresponding stabilized operator, which is necessary for the error analysis. As the main theme of this work, we prove the error bounds for the concentrations and for the concentration gradients, driven by a large amount of weighted energy-like controls involving the expectation operator. Compared to the classical error bounds in L-2 and H-1 that we obtained in the previous studies, our analysis here needs a higher smoothness of the true terminal data to ensure their reconstructions from the stochastic fashion. Two numerical examples are provided to corroborate the theoretical results. Published by Elsevier B.V.V.A. Khoa was funded by US Army Research Laboratory and US Army Research Office grant W911NF-19-1-0044. V.A. Khoa's work was also partly supported by the Research Foundation-Flanders (FWO), Belgium under the project named "Approximations for forward and inverse reaction-diffusion problems related to cancer models''. N.H. Tuan and V.V. Au are funded by Vietnam National University Ho Chi Minh City (VNU-HCM) under Grant No. B2020-18-03.Khoa, VA (corresponding author), Univ North Carolina Charlotte, Dept Math & Stat, Charlotte, NC 28223 USA.
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Uniqueness result for an age-dependent reaction-diffusion problem
No full textThis paper is concerned with an age-structured model in population dynamics. We investigate the uniqueness of solution for this type of nonlinear reaction-diffusion problem when the source term depends on the density, indicating the presence of, for example, mortality and reaction processes. Our result shows that in a spatial environment, if two population densities obey the same evolution equation and possess the same terminal data of time and age, then their distributions must coincide therein.This work is in commemoration of the first death anniversary of V. A. K's father. V. A. K thanks Prof. Nguyen Huy Tuan for introducing him the ultraparabolic problem. The work of V.A.K. was supported by the Research Foundation-Flanders (FWO) under the project 'Approximations for forward and inverse reaction-diffusion problems related to cancer models'.Lesnic, D (reprint author), Univ Leeds, Dept Appl Math, Leeds, W Yorkshire, England.
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Path planning for autonomous ships: A hybrid approach based on improved apf and modified vo methods
No full textIn this research, a hybrid approach for path planning of autonomous ships that generates both global and local paths, respectively, is proposed. The global path is obtained via an improved artificial potential field (APF) method, which makes up for the shortcoming that the typical APF method easily falls into a local minimum. A modified velocity obstacle (VO) method that incorpo-rates the closest point of approach (CPA) model and the International Regulations for Preventing Collisions at Sea (COLREGS), based on the typical VO method, can be used to get the local path. The contribution of this research is two-fold: (1) improvement of the typical APF and VO methods, making up for previous shortcomings, and integrated COLREGS rules and good seamanship, making the paths obtained more in line with navigation practice; (2) the research included global and local path planning, considering both the safety and maneuverability of the ship in the process of avoiding collision, and studied the whole process of avoiding collision in a relatively entirely way. A case study was then conducted to test the proposed approach in different situations. The results indicate that the proposed approach can find both global and local paths to avoid the target ship.</p
Efficient finite-difference method for computing sensitivities of biochemical reactions
No full textSensitivity analysis of biochemical reactions aims at quantifying the dependence of the reaction dynamics on the reaction rates. The computation of the parameter sensitivities, however, poses many computational challenges when taking stochastic noise into account. This paper proposes a new finite-difference method for efficiently computing sensitivities of biochemical reactions. We employ propensity bounds of reactions to couple the simulation of the nominal and perturbed processes. The exactness of the simulation is preserved by applying the rejection-based mechanism. For each simulation step, the nominal and perturbed processes under our coupling strategy are synchronized and often jump together, increasing their positive correlation and hence reducing the variance of the estimator. The distinctive feature of our approach in comparison with existing coupling approaches is that it only needs to maintain a single data structure storing propensity bounds of reactions during the simulation of the nominal and perturbed processes. Our approach allows to compute sensitivities of many reaction rates simultaneously. Moreover, the data structure does not require to be updated frequently, hence improving the computational cost. This feature is especially useful when applied to large reaction networks. We benchmark our method on biological reaction models to prove its applicability and efficiency. © 2018 The Author(s) Published by the Royal Society. All rights reserved
Strong convergence of a linearization method for semi-linear elliptic equations with variable scaled production
No full textThis work is devoted to the development and analysis of a linearization algorithm for microscopic elliptic equations, with scaled degenerate production, posed in a perforated medium and constrained by the homogeneous Neumann-Dirichlet boundary conditions. This technique plays two roles: to guarantee the unique weak solvability of the microscopic problem and to provide a fine approximation in the macroscopic setting. The scheme systematically relies on the choice of a stabilization parameter in such a way as to guarantee the strong convergence in H-1 norm for both the microscopic and macroscopic problems. In the standard variational setting, we prove the H-1-type contraction at the micro-scale based on the energy method. Meanwhile, we adopt the classical homogenization result in line with corrector estimate to show the convergence of the scheme at the macro-scale. In the numerical section, we use the standard finite element method to assess the efficiency and convergence of our proposed algorithm.V.A.K. thanks Prof. Adrian Muntean for being his supervisor since March, 2015 and for giving him invaluable advice. V.A.K thanks Prof. Iuliu Sorin Pop (Hasselt, Belgium) for recent supports in his research career and acknowledges the hospitality of the Hasselt University during the time he is hosted as a postdoctoral fellow. N.N.N. acknowledges the support of the project INdAM Doctoral Programme in Mathematics and/or Applications Cofunded by Marie Sklodowska-Curie Actions, acronym: INdAM-DP-COFUND-2015, grant number: 713485.Ngoc, NN (corresponding author), Politecn Milan, Dipartimento Matemat, I-20133 Milan, Italy.
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The ‘Galilean Style in Science’ and the Inconsistency of Linguistic Theorising
No full textChomsky’s principle of epistemological tolerance says that in theoretical linguistics contradictions between the data and the hypotheses may be temporarily tolerated in order to protect the explanatory power of the theory. The paper raises the following problem: What kinds of contradictions may be tolerated between the data and the hypotheses in theoretical linguistics? First a model of paraconsistent logic is introduced which differentiates between week and strong contradiction. As a second step, a case study is carried out which exemplifies that the principle of epistemological tolerance may be interpreted as the tolerance of week contradiction. The third step of the argumentation focuses on another case study which exemplifies that the principle of epistemological tolerance must not be interpreted as the tolerance of strong contradiction. The reason for the latter insight is the unreliability and the uncertainty of introspective data. From this finding the author draws the conclusion that it is the integration of different data types that may lead to the improvement of current theoretical linguistics and that the integration of different data types requires a novel methodology which, for the time being, is not available
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