QUASII: QUery-Aware Spatial Incremental Index.

With large-scale simulations of increasingly detailed models and improvement of data acquisition technologies, massive amounts of data are easily and quickly created and collected. Traditional systems require indexes to be built before analytic queries can be executed efficiently. Such an indexing step requires substantial computing resources and introduces a considerable and growing data-to-insight gap where scientists need to wait before they can perform any analysis. Moreover, scientists often only use a small fraction of the data - the parts containing interesting phenomena - and indexing it fully does not always pay off. In this paper we develop a novel incremental index for the exploration of spatial data. Our approach, QUASII, builds a data-oriented index as a side-effect of query execution. QUASII distributes the cost of indexing across all queries, while building the index structure only for the subset of data queried. It reduces data-to-insight time and curbs the cost of incremental indexing by gradually and partially sorting the data, while producing a data-oriented hierarchical structure at the same time. As our experiments show, QUASII reduces the data-to-insight time by up to a factor of 11.4x, while its performance converges to that of the state-of-the-art static indexes

Evaluation of magnetic materials for static inverters and converters

Program studies materials for use in static inverters and converters. It gives suitable data on the behavior of commonly used materials when excited with square wave power

Highly efficient fe simulations by means of simplified corotational formulation

Finite Element Method (FEM) has deservedly gained the reputation of the most powerful numerical method in the field of structural analysis. It offers tools to perform various kinds of simulations in this field, ranging from static linear to nonlinear dynamic analyses. In recent years, a particular challenge is development of FE formulations that enable highly efficient simulations, aiming at real-time dynamic simulations as a final objective while keeping high simulation fidelity such as nonlinear effects. The authors of this paper propose a simplified corotational FE formulation as a possible solution to this challenge. The basic idea is to keep the linear behavior of each element in the FE assemblage, but to extract the rigid-body motion on the element level and include it in the formulation to cover geometric nonlinearities. This paper elaborates the idea and demonstrates it on static cases with three different finite element types. The objective is to check the achievable accuracy based on such a simplified geometrically nonlinear FE formulation. In the considered examples, the difference between the results obtained with the present formulation and those by rigorous formulations is less than 3% although fairly large deformations are induced

Environmental study of some metals on several aquatic macrophytes

Aquatic macrophytes can be used in the study of quality of water ecosystems and in monitoring of metals and other pollutants. This study was focused on assessment of metals accumulation in certain aquatic macrophytes (biomonitors), in comparison with water and sediment (abiotic monitors) of the lake. Concentrations of Fe, Mn, Cu and Pb were measured in water, sediment and plant samples, namely in stems and leaves of Bidens tripartitus L., Polygonum amphibium L., Lycopus europaeus L. and in roots, stems and leaves of two aquatic plants, Typha angustifolia L. and Typha latifolia L. The concentrations of all investigated metals were higher in sediment than in water. The mean concentrations of metals in macrophytes were sequenced: Fe > Mn > Cu > Pb. This study exhibited different metals concentration in aquatic plants, depending on the plant organ. The highest concentrations of Fe and Pb were recorded in root of T.latifolia L. As means of Mn and Cu, their concentrations were higher in stems and leaves of different investigated species. The application of macrophytes can be possible in finding of solutions for problems of protection, sanation and revitalization of different aquatic ecosystems.Key words: Aquatic macrophytes, metals (Fe, Mn, Cu and Pb), lake contamination

Modelling and analyzing adaptive self-assembling strategies with Maude

Building adaptive systems with predictable emergent behavior is a challenging task and it is becoming a critical need. The research community has accepted the challenge by introducing approaches of various nature: from software architectures, to programming paradigms, to analysis techniques. We recently proposed a conceptual framework for adaptation centered around the role of control data. In this paper we show that it can be naturally realized in a reflective logical language like Maude by using the Reflective Russian Dolls model. Moreover, we exploit this model to specify and analyse a prominent example of adaptive system: robot swarms equipped with obstacle-avoidance self-assembly strategies. The analysis exploits the statistical model checker PVesta

Dispersion and polarization conversion of whispering gallery modes in arbitrary cross-section nanowires

We investigate theoretically the optical properties of Nano-Wires (NWs) with cross sections having either discrete or cylindrical symmetry. The material forming the wire is birefringent, showing a different dielectric response in the plane and along the axis of the wire, which is typically the case for wires made of wurtzite materials, such as ZnO or GaN. We look for solutions of Maxwell`s equations having the proper symmetry. The dispersions and the linewidths versus angle of incident light for the modes having high momentum in the cross-section plane, so called whispering gallery modes, are calculated. We put a special emphasis on the case of hexagonal cross sections. The energy positions of the modes for a set of azimuthal quantum numbers are shown. We demonstrate the dependence of the energy splitting between TE and TM modes versus birefringence. The polarization conversion from TE to TM with increase of the axial wave vectoris discussed for both cylindrical and discrete symmetry.Comment: 9 pages, 10 figure

On the new very early table varieties obtained by crossing different varieties of grapevine

In order to obtain new table grape varieties which ripen before or at the same time as variety Pearl of Csaba, we performed many intervarietal crossings at our experimental station, using the following parents: Pearl of Csaba, Chasselas Bouvier, Muscat Ottonel, Queen of Vineyard, Cardinal, Dattier de Beyrouth, Ribier.The Government Commission acknowledged five very early varieties, three of which have also better agrobiological and technological characteristics than the variety Pearl of Csaba.The new variety Demir Door ripens on average 6 d, the new variety Early of Belgrade 3-5 d earlier, and the new variety Grochanka ripens at the same time or 1-3 d later as the control variety Pearl of Csaba.Due to multiple regression analysis, biological characteristics as yield, cluster and berry weights and sugar content strongly depend on meteorological conditions (temperature, rainfall and solar radiation); this is valid for all the new varieties and the variety Pearl of Csaba at all locations investigated.Analysis of variance (level of 0.05 and 0.01) shows that compared to the control variety we obtained with new varieties significantly greater yields, very significant large cluster and berry weights and very significantly better uvological characteristics of berry. The average yields for all investigated locations were increased in comparison to the control variety Pearl of Csaba: Demir Door +3.004 kg/ha, Early of Belgrade +6.259 kg/ha, Grochanka +7.065 kg/ha.Organoleptic characteristics are much improved with all new varieties which is illustrated by increased indexes.All investigated varieties are acknowledged genotypes of Vitis vinifera L, and all of these new varieties exhibited better biological and technological parameters than Pearl of Csaba

Space odyssey: efficient exploration of scientific data.

Advances in data acquisition---through more powerful supercomputers for simulation or sensors with better resolution---help scientists tremendously to understand natural phenomena. At the same time, however, it leaves them with a plethora of data and the challenge of analysing it. Ingesting all the data in a database or indexing it for an efficient analysis is unlikely to pay off because scientists rarely need to analyse all data. Not knowing a priori what parts of the datasets need to be analysed makes the problem challenging. Tools and methods to analyse only subsets of this data are rather rare. In this paper we therefore present Space Odyssey, a novel approach enabling scientists to efficiently explore multiple spatial datasets of massive size. Without any prior information, Space Odyssey incrementally indexes the datasets and optimizes the access to datasets frequently queried together. As our experiments show, through incrementally indexing and changing the data layout on disk, Space Odyssey accelerates exploratory analysis of spatial data by substantially reducing query-to-insight time compared to the state of the art