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71.
Constraint preconditioners have proved very efficient for the solution of ill-conditioned finite element (FE) coupled consolidation
problems in a sequential computing environment. Their implementation on parallel computers, however, is not straightforward
because of their inherent sequentiality. The present paper describes a novel parallel inexact constraint preconditioner (ParICP)
for the efficient solution of linear algebraic systems arising from the FE discretization of the coupled poro-elasticity equations.
The ParICP implementation is based on the use of the block factorized sparse approximate inverse incomplete Cholesky preconditioner,
which is a very recent and effective development for the parallel preconditioning of symmetric positive definite matrices.
The ParICP performance is experimented with in real 3D coupled consolidation problems, proving a scalable and efficient implementation
of the constraint preconditioning for high-performance computing. ParICP appears to be a very robust algorithm for solving
ill-conditioned large-size coupled models in a parallel computing environment. 相似文献
72.
The maximum sustainable yield concept (MSY) and the ecosystem approach to fisheries management (EAFM) have been recently adopted by the European Commission with the objective to achieve, over the long term, the highest possible sustainable yield from a given exploited stock. In this context, a fishing mortality MSY reference level (i.e., FMSY) should be defined, taking into account recruitment, growth and natural mortality under current or recent ecosystem conditions. Thus, FMSY is used as a generic term for a robust estimate of a fishing mortality level that is associated with high sustainable yield in the long term, assuming the current harvesting regime in terms of size selectivity. In this study, using the Eastern Baltic cod as an example, we challenge this rather simplified view showing that by using a different harvest selectivity and thus changing the size range of harvested cod, it is possible to largely increase the yield and revenue from the fishery compared to the fishing mortality stipulated in the management plan (i.e., FMSY), while assuring sustainable high yield in the long term. Thus, implementing the MSY concept in terms of fishing mortality but neglecting selective harvesting effects will not achieve high long term sustainable yield for Eastern Baltic cod. The combination of size selective harvesting and economic reasoning may offer an important tool for the management of marine resources by potentially providing a common currency for the different stakeholders and offer guidance to achieve long term sustainability and human well-being. This would represent the natural step forward in the implementation of EAFM and MSY concepts. 相似文献
73.
The Calatabiano landslide (southern Italy): preliminary GB-InSAR monitoring data and remote 3D mapping 总被引:1,自引:1,他引:0
Luca Lombardi Massimiliano Nocentini William Frodella Teresa Nolesini Federica Bardi Emanuele Intrieri Tommaso Carlà Lorenzo Solari Giulia Dotta Federica Ferrigno Nicola Casagli 《Landslides》2017,14(2):685-696
On 24 October 2015, following a period of heavy rainfall, a landslide occurred in the Calatabiano Municipality (Sicily Island, Southern Italy), causing the rupture of a water pipeline supplying water to the city of Messina. Following this event, approximately 250,000 inhabitants of the city suffered critical water shortages for several days. Consequently, on 6 November 2015, a state of emergency was declared (O.C.D.P. 295/2015) by the National Italian Department of Civil Protection (DPC). During the emergency management phase, a provisional by-pass, consisting of three 350-m long pipes passing through the landslide area, was constructed to restore water to the city. Furthermore, on 11 November 2015, a landslide remote-sensing monitoring system was installed with the following purposes: (i) analyse the landslide geomorphological and kinematic features in order to assess the residual landslide risk and (ii) support the early warning procedures needed to ensure the safety of the personnel involved in the by-pass construction and the landslide stabilization works. The monitoring system was based on the combined use of Ground-Based Interferometric Synthetic Aperture Radar (GB-InSAR) and terrestrial laser scanning (TLS). In this work, the preliminary results of the monitoring activities and a remote 3D map of the landslide area are presented. 相似文献
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Thébault H Rodriguez Y Baena AM Andral B Barisic D Albaladejo JB Bologa AS Boudjenoun R Delfanti R Egorov VN El Khoukhi T Florou H Kniewald G Noureddine A Patrascu V Pham MK Scarpato A Stokozov NA Topcuoglu S Warnau M 《Marine pollution bulletin》2008,57(6-12):801-806
The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify (137)Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured (137)Cs levels were found to be very low (usually < 1 Bq kg(-1) wet wt) (137)Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area. 相似文献
79.
Vasile Mioc 《Astronomische Nachrichten》1980,301(6):311-315
On donne une expression analytique de la différence causée par le frottement atmosphérique entre les périodes nodale et képlérienne des satellites artificiels aux orbites quasi-circulaires, évoluant dans une atmosphère à symétrie sphéque. Quelques équations correspondantes trouvées par divers auteurs sont obtenues en tant que cas particuliers de l'équation donnée. 相似文献
80.
重点介绍和讨论了中性条件下旋转扰动流体中边界层强迫不稳定及其相关的一些问题,阐述了旋转体系中切变驱动边界层不稳定的动力学特征.这些不稳定状态的研究在大气物理学、流体动力学、海洋学等多个领域中引起科学家极大的兴趣,近年来在实验和理论研究中都得到了不断的发展.意大利都灵大学基础物理系地球科学实验组通过水槽旋转实验方法,不断改变水槽启动或结束时的旋转运动速度,以及底部壁面粗糙度等要素,所得到的实验结果与SDBL理论非常一致. 相似文献