Baltic Sea waves analysis by using chaos theory tools, Computer Systems Engeneering: Theory and Applications

The motivation for this paper was to assess the applicability of the novel approach derived from chaos theory to the description and analysis of dynamics of the free sea surface, in particular to the phase space reconstruction of the dynamical system from the observed time series. The free sea surface elevation data sets were sampled at the Baltic Coastal Research Station Lubiatowo in Poland. After proper processing the experimental data, it was found that the sea surface elevations can be described as a result of a four-dimensional process, which appears to be weakly chaotic, characterized by a positive largest Lyapunov exponent and a short prediction horizon. It was confirmed that using chaos theory tools may be very promising for diagnosing certain properties of the sea waves. Moreover, in the paper, some new technique for evaluation of the average mutual information is introduced

Quantization with Knowledge Base Applied to Geometrical Nesting Problem

Nesting algorithms deal with placing two-dimensional shapes on the given canvas. In this paper a binary way of solving the nesting problem is proposed. Geometric shapes are quantized into binary form, which is used to operate on them. After finishing nesting they are converted back into original geometrical form. Investigations showed, that there is a big influence of quantization accuracy for the nesting effect. However, greater accuracy results with longer time of computation. The proposed knowledge base system is able to strongly reduce the computational time

Vertical mixing and coherent anticyclones in the ocean: the role of stratification

The role played by wind-forced anticyclones in the vertical transport and mixing at the ocean mesoscale is investigated with a primitive-equation numerical model in an idealized configuration. The focus of this work is to determine how the stratification impacts such transport. <br><br> The flows, forced only at the surface by an idealized wind forcing, are predominantly horizontal and, on average, quasigeostrophic. Inside vortex cores and intense filaments, however, the dynamics is strongly ageostrophic. <br><br> Mesoscale anticyclones appear as "islands" of increased penetration of wind energy into the ocean interior and they represent the maxima of available potential energy. The amount of available potential energy is directly correlated with the degree of stratification. <br><br> The wind energy injected at the surface is transferred at depth through the generation and subsequent straining effect of Vortex Rossby Waves (VRWs), and through near-inertial internal oscillations trapped inside anticyclonic vortices. Both these mechanisms are affected by stratification. Stronger transfer but larger confinement close to the surface is found when the stratification is stronger. For weaker stratification, vertical mixing close to the surface is less intense but below about 150 m attains substantially higher values due to an increased contribution of both VRWs, whose time scale is on the order of few days, and of near-inertial motions, with a time scale of few hours

Finding the relationship between Instructional strategies and Student Learning Styles in Online learning

Researchers investigated differences in learner preferences for different types of instructional strategies and learning styles in online environments. Results suggested that matches between students’ learning styles and instructional strategies did not affect their perception of their own learning outcomes, level of effort and involvement, and level of interactions in the course. Data also indicated that no single instructional strategy, among three instructional strategies tested, emerged as superior for high and low field dependent online students

Produttivita primaria dell' ecosistema marino, turbolenza oceanica e cicli biogeochimici globali

Il ciclo globale del carbonio e la concentrazione atmosferica di CO2 sono influenzati dai flussi biogeochimici fra oceano ed atmosfera. Questi flussi dipendono dal funzionamento dell’ecosistema marino; modifiche significative nella dinamica del plancton e nella produttività primaria possono avere rilevanti effetti sul clima. La dinamica del plancton, a sua volta, risente degli effetti di trasporto e rimescolamento indotti dalle strutture a mesoscala quali vortici e fronti, che per questo motivo sono uno degli attori sulla scena della dinamica del clim

Observed and modeled surface eddy heat fluxes in the eastern Nordic Seas

Large-scale budget calculations and numerical model process studies suggest that lateral eddy heat fluxes have an important cooling effect on the Norwegian Atlantic Current (NwAC) as it flows through the Nordic Seas. But observational estimates of such fluxes have been lacking. Here, wintertime surface eddy heat fluxes in the eastern Nordic Seas are estimated from surface drifter data, satellite data and an eddy-permitting numerical model. Maps of the eddy heat flux divergence suggest advective cooling along the path of the NwAC. Integrating the flux divergence over temperature classes yields consistent estimates for the three data sets; the waters warmer than about 6°C are cooled while the cooler waters are warmed. Similar integrations over bottom depth classes show that regions shallower than about 2000 m are cooled while deeper regions are warmed. Finally, integrating the flux divergence along the core of the NwAC suggests that the highest eddy-induced heat loss at the surface is along the steepest part of the continental slope, east of the Lofoten Basin. The model fields indicate that cooling of the current by lateral eddy fluxes is comparable to or larger than the local heat loss to the atmosphere

Web-Based Instruction and Learning: Analysis and Needs Assessment

An analysis and needs assessment was conducted to identify kindergarten through grade 14 (K-14) customer needs with regard to using the World Wide Web (WWW) for instruction and to identify obstacles K-14 teachers face in utilizing NASA Learning Technologies products in the classroom. The needs assessment was conducted as part of the Dryden Learning Technologies Project which is a collaboration between Dryden Flight Research Center (DFRC), Edwards, California and Tne Pennsylvania State University (PSU), University Park, Pennsylvania. The overall project is a multiyear effort to conduct research in the development of teacher training and tools for Web-based science, mathematics and technology instruction and learning