Search results for "Disc"
showing 10 items of 19256 documents
Combined column-and-row-generation for the optimal communication spanning tree problem
2018
Abstract This paper considers the exact solution of the optimal communication spanning tree problem (OCSTP), which can be described as follows: Given an undirected graph with transportation costs on every edge and communication requirements for all pairs of vertices, the OCSTP seeks for a spanning tree that minimizes the sum of the communication costs between all pairs of vertices, where the communication cost of a pair of vertices is defined as their communication requirement multiplied by the transportation cost of the unique tree path that connects the two vertices. Two types of compact formulations for OCSTP were presented in the literature. The first one is a four-index model based on …
Variable neighborhood descent for the incremental graph drawing
2017
Abstract Graphs are used to represent reality in several areas of knowledge. Drawings of graphs have many applications, from project scheduling to software diagrams. The main quality desired for drawings of graphs is readability, and crossing reduction is a fundamental aesthetic criterion for a good representation of a graph. In this paper we target the edge crossing reduction in the context of incremental graph drawing, in which we want to preserve the layout of a graph over successive drawings. We propose a hybrid method based on the GRASP (Greedy Randomized Adaptive Search Procedure) and VND (Variable Neighborhood Descent) methodologies and compare it with previous methods via simulation.
Determination of Sorption Properties of Heavy Metals in Various Biosorbents
2018
Abstract Various techniques of determination of properties of physicochemical processes of heavy metal sorption in biosorbents were analysed. The methods of preparing and storing samples, conditions of experiment performance, as well as the methods of data interpretation were discussed. Two procedures of study were analysed: (1) in the static system of biosorbent-solution contact and (2) in the system of dynamic flow of solution. Copper cation sorption was studied. The effect of consecutive stages of the study on the quality of final results was shown. A high degree of uncertainty of the sorption capacity assessment was reported, which was dependent on the manner of conducting the study. Th…
A risk assessment proposal for underground cavities in Hard Soils-Soft Rocks
2018
Abstract Underground calcarenite quarries in Marsala (Sicily) have been involved in a number of collapses that have, seriously damaged numerous buildings. The stability conditions were therefore examined in order to assess risk conditions within the historical centre of the town and the surrounding areas, which are subject to urban expansion. Starting with an extensive collection of historical information, the research was carried out through surveys of the cavities, systematic sampling of material, petrographic analysis and geotechnical testing. The results of laboratory tests and in situ investigations provided a geotechnical characterization of both the intact material and the rock mass.…
From metaphor to action : embodied language cognition
2016
Las teorias que tradicionalmente han tratado de explicar como la actividad cerebral da lugar a la cognicion se han servido de la metafora del ordenador para describir que el modo en que el cerebro procesa informacion es transformandola en un codigo de simbolos que pueden combinarse entre si siguiendo un conjunto finito de reglas. Sin embargo, recientes estudios, con paradigmas actualizados y ayudandose de las tecnicas de neuroimagen, nos muestran que las actividades cerebrales que registramos cuando observamos un cerebro implicado en alguna tarea cognitiva son las mismas que observariamos si ese cerebro se encontrase inmerso en el procesamiento perceptivo, motor o emocional de la informaci…
Automatic Location of Sources of Electrical Activation from Electroanatomical Maps
2016
Electro-anatomical mapping is a widely used technique used by electrophysiologists to understand patient's activation pattern. The system measures activation time at different locations but does not provide information on underlying electrical pathways or triggering points, such as Purkinje-myocardial junctions or ectopic foci. We present a method to estimate the locations of Purkinje-myocardial junctions from a discrete set of endocardial samples. Using less than 1000 endocardial samples it can recover locations and activation times of the most influencing Purkinje myocardial junctions from Purkinje trees of up to 500 junctions. A simulation study revealed that using the estimated Purkinje…
Graph Rewriting Based Search for Molecular Structures: Definitions, Algorithms, Hardness
2018
We define a graph rewriting system that is easily understandable by humans, but rich enough to allow very general queries to molecule databases. It is based on the substitution of a single node in a node- and edge-labeled graph by an arbitrary graph, explicitly assigning new endpoints to the edges incident to the replaced node. For these graph rewriting systems, we are interested in the subgraph-matching problem. We show that the problem is NP-complete, even on graphs that are stars. As a positive result, we give an algorithm which is polynomial if both rules and query graph have bounded degree and bounded cut size. We demonstrate that molecular graphs of practically relevant molecules in d…
Synthesis and Cytotoxicity of 1,4-Dihydropyridines and an Unexpected 1,3-Oxazin-6-one
2016
Eight heterocycles have been prepared in a one-pot reaction manner based on the Hantzsch dihydropyridine synthesis. The synthesis afforded seven dihydropyridines (DHP) and one unexpected 1,3-oxazin-6-one. Their structures were confirmed based on NMR spectroscopy and mass spectrometry. The obtained products have been evaluated for their cytotoxicity against eight cancer cell lines and one normal cell line. Two halogenated DHPs (7 and 8) displayed cytotoxicity toward all the nine tested cancer cell lines with IC50 values from 4.10 to 58.90 μm, while others showed selective activities. DHPs (7 and 8) bearing a Me group at C(2) and C(6) as well as a halogenated substituent at C(4′) were more an…
Ancient cattle genomics, origins, and rapid turnover in the Fertile Crescent
2019
Cattle were domesticated ∼10,000 years ago, but analysis of modern breeds has not elucidated their origins. Verdugo et al. performed genome-wide analysis of 67 ancient Near Eastern Bos taurus DNA samples. Several populations of ancient aurochs were progenitors of domestic cows. These genetic lineages mixed ∼4000 years ago in a region around the Indus Valley. Interestingly, mitochondrial analysis indicated that genetic material likely derived from arid-adapted Bos indicus (zebu) bulls was introduced by introgression.Science, this issue p. 173Genome-wide analysis of 67 ancient Near Eastern cattle, Bos taurus, remains reveals regional variation that has since been obscured by admixture in mode…
A time-varying observer for linear systems with asynchronous discrete-time measurements
2017
International audience; In this paper we propose a time-varying observer for a linear continuous-time plant with asynchronous discrete-time measurements. The proposed observer is contextualized in the hybrid systems framework providing an elegant setting for the proposed solution. In particular some theoretical tools are provided, in terms of LMIs, certifying asymptotic stability of a certain compact set where the estimation error is zero. Moreover the case of asynchronous measurements is considered, i.e. when the measurements are not provided in well defined time instants, but they occur at an arbitrary time in a certain time interval. A design procedure based on the numerical solution of …