109 research outputs found
Clematis occidentalis (Virgen's Bower) : Virgen's Bower
No full textClass: Dicotyledoneae
Family: Ranunculaceae
Genus: Clematis
Species: occidentali
Efficient Management of Resources and Entities using the HyVonNe P2P Architecture
No full textGrid and P2P environments often require to manage a wide number of distributed and mobile entities. In this paper we present a scalable partitioning technique of the entity space, based on Voronoi diagrams, that is well-suited for distributed applications with dynamically changing topology. In HyVonNe (Hybrid Voronoi Network) architecture, the entity space is partitioned in Voronoi regions, each one including a limited number of entities and managed by a Region Leader. Regions are created and deleted depending on the spatial density of entities and the resulting Overlay Network is used to support routing and searching activities. This two-layered structure (entity space and Voronoi regions) is scalable, extendable, and allows to reduce the propagation of the entity position updates in the network and to maintain the load balancing among regions. The fault tolerance features of HyVonNe are studied as well, simulating two different applications in Grid and P2P environments
Quality of Service on Grid: Architectural and methodological issues
No full textIn ten years of evolution Grid Computing has changed quickly, and the development of new middleware services makes Grid platforms increasingly used not only for best effort large scientific jobs but also in industrial and business applications. This has taken to a growing demand of Quality of Service (QoS) support, strongly driven by the requirements
of the new potential applications. However, the QoS issue on Grid is not easy, as Grid has been originally designed without any QoS support, and it is a complex system. During years some solutions have been proposed to implement, usually over middleware, the
functionalities needed to supply QoS for specific classes of applications. This results in a focused and heterogeneous approach, so that it is hard to evaluate both the sufficiency of the support and its robustness with respect to the large spectrum of possible Grid applications. In this context, our contribution concerns three points: first, we analyze the current approach to QoS on Grid as a relationship among QoS features, applications and
architectures; second, we evaluate the QoS requirements of two recent QoS-demanding applications on Grid, namely Massive Multiplayer Online Games (MMOG) and Urgent Computing, comparing these requirements with the support provided by current QoS architectures; third, as a result of our analysis, we propose some guidelines for an alternative approach to QoS provision on Grid, based on the definition of a dedicated QoS-management layer to overcome the limitation of the current methodologies
Clematis flore pleno, Bursa pastoris
No full text1. Nome scientifico: Capsella bursa-pastoris (L.) Medicus
(Brassicaceae, Cruciferae)
Nome attuale: Borsa di pastore
2. Nome scientifico: Clematis viticella L.
(Ranunculaceae)
Nome attuale: Viticell
Cytotoxic triterpenoid saponins from Clematis tangutica
No full textEight previously undescribed oleanane-type triterpenoid saponins, clematangoticosides A-H, together with eight known saponins, were isolated from the whole plants of Clematis tangutica (Maxim.) Korsh. Their structures were elucidated by extensive spectroscopic analysis, in combination with chemical methods (acid hydrolysis and mild alkaline hydrolysis). Clematangoticosides D-G were found to be unusual 23, 28-bidesmosidic glycosides. The cytotoxic activities of all of the isolated saponins were evaluated against the four human cancer cell lines SGC-7901, HepG2, HL-60 and U251MG. Clematoside S, sapindoside B, kalopanax saponin A, and koelreuteria saponin A exhibited cytotoxicity against all of the test cancer cell lines with 1050 values in the range of 1.88-27.20 mu M, while clematangoticoside D and F showed selective cytotoxicity against SGC-7901 with IC50 values of 24.22 and 2135 mu M, respectively. (C) 2016 Elsevier Ltd. All rights reserved
Electrochemical removal of Terbuthylazine:Boron-Doped Diamond anode coupled with solid polymer electrolyte
No full textTerbuthylazine (TBA) has replaced atrazine in many EU countries, becoming one of the most frequently detected pesticides in natural waters. TBA is a compound of emerging concern, due to its persistence, toxicity and proven endocrine disruption activity to wildlife and humans. Techniques applied in water treatment plants remove only partially this herbicide and poor attention is given to the generation and fate of by-products, although some of them have demonstrated an estrogenic activity comparable to atrazine. This paper summarizes the environmental occurrence of TBA and its main metabolite desethylterbuthylazine and reports the performance of an innovative electrochemical cell equipped with a solid polymer electrolyte (SPE) sandwiched between a Ti/RuO2 cathode and a Boron-Doped Diamond anode, operating at constant current, in the treatment of an aqueous solution of TBA. The herbicide removal in the first 30 min of treatment increases from 42% to 92% as the applied current is increased from 100 to 500 mA. The rate of degradation at 500 mA decreases between 30 and 60 min, with a final abatement of 97%. An 89% removal was reached at 100 mA when the initial TBA concentration was raised from 0.1 to 4 mg L−1 and less than 1% of the herbicide was converted in desethylterbuthylazine and minor metabolites. No chemicals are needed, no sludge is produced. Further research is encouraged, as this technology may be promising for the achievement of a zero-discharge removal of different emerging pollutants as pesticides, pharmaceuticals and personal care products
Load Balancing and Computing Strategies in Pipeline Optimization for Parallel Visualization of 3D Irregular Meshes
No full textParallel visualization is assuming an increasing role in the deployment of Web and Grid based systems for scientific applications. The visualization process consists of a set of filters or components that are executed in a pipelined assembly that should be adaptively configured on the basis of user requirements, processing architecture and network characteristics. In this paper we focus our attention on the visualization of 3D irregular meshes produced by the interrogation of volumetric data using an isosurface extraction algorithm. We consider a simplified pipeline consisting of two components: isosurface extraction, and mesh simplification. We show that also in this simple case an in-deep analysis is necessary in order to optimize the whole pipeline. In fact different implementation and load balancing strategies are possible for each single component, but the whole pipeline optimization could be achieved combining non-optimal implementation of individual stages. Moreover the quality of the produced mesh should be considered in the selection of an adequate component implementation. The proposed analysis permits to point out trade-offs and algorithmic requirements that should be considered in the design of a complete visualization system for advanced Grid applications
An Online Parallel Algorithm for Remote Visualization of Isosurfaces
No full textIn this paper we present a parallel algorithm, implemented using MPICH, for isosurface extraction from volumetric data sets. The main contribution of this paper is in the analysis and performance improvements of the different phases of the isosurface production process including computation and output generation. The resulting algorithm is particularly well suited for online applications and for remote results visualization
A Local Decision Algorithm for Maximum Lifetime in ad Hoc Networks
No full textMobile hosts of ad-hoc networks operate on battery, hence optimization of system lifetime, intended as maximization of the time until the first host drains-out its battery, is an important issue. Some routing algorithms have already been proposed, that require the knowledge of the future behavior of the system, and/or complex routing information. We propose a novel routing algorithm that allows each host to locally select the next routing hop, having only immediate neighbor information, to optimize the system lifetime. Simulation results of runs performed in different scenarios are finally shown
SoRTSim: A High-Level Simulator for the Evaluation of QoS Models on Grid
No full textWe present SoRTSim, a high-level simulator designed to evaluate tools built over the middleware to support additional services besides the standard ones, particularly to allow the execution on Grid platforms of applications with strict QoS requirements, up to Soft Real-Time. SoRTSim has been designed to be quite general and to be easily customized for different tools and classes of applications. We describe the SoRTSim architecture and its implementation, highlighting its main features. The simulator allows the easy generation of a high number of abstract Grid scenarios, starting from a set of constraints; supports the definition of the various Grid entities and their behaviour; and makes simple the evaluation of performance, based on user-defined metrics and statistics. As a case study, we show how SoRTSim can be used to simulate SoRTGrid, a framework that we previously developed for managing time constraints on a Service-oriented Grid
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