Geospace Environment Modeling 2008–2009 Challenge: Geosynchronous magnetic field

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94577/1/swe422.pd

A Multi Level Multi Domain Method for Particle In Cell Plasma Simulations

A novel adaptive technique for electromagnetic Particle In Cell (PIC) plasma simulations is presented here. Two main issues are identified in designing adaptive techniques for PIC simulation: first, the choice of the size of the particle shape function in progressively refined grids, with the need to avoid the exertion of self-forces on particles, and, second, the necessity to comply with the strict stability constraints of the explicit PIC algorithm. The adaptive implementation presented responds to these demands with the introduction of a Multi Level Multi Domain (MLMD) system (where a cloud of self-similar domains is fully simulated with both fields and particles) and the use of an Implicit Moment PIC method as baseline algorithm for the adaptive evolution. Information is exchanged between the levels with the projection of the field information from the refined to the coarser levels and the interpolation of the boundary conditions for the refined levels from the coarser level fields. Particles are bound to their level of origin and are prevented from transitioning to coarser levels, but are repopulated at the refined grid boundaries with a splitting technique. The presented algorithm is tested against a series of simulation challenges

Use of Mobile Technology in Teaching English Vocabulary

Tehnoloģija pastāvīgi maina izglītības vidi, kā arī mācību un mācīšanas pieredzi. Tādēļ tas ir tikai pašsaprotami, ka mobilo ierīču izmantošana valodu apguvē ir kļuvusi par plaši izplatītu mūsdienas tendenci. Neskatoties uz to, tikai dažos pētījumos ir izpētīta mobilo tehnoloģiju lietojums angļu valodas mācīšanā Latvijā. Pašreizējais pētījums bija vērsts uz to, lai pārbaudītu, vai mobilās tehnoloģijas var potenciāli veicināt angļu vārdu krājuma apguvi, jo īpaši attiecībā uz vārdkopu apguvi. Šajā nolūkā tika savākti nepieciešamie dati par mobilo ierīču un netehnoloģisko līdzekļu izmantošanas efektivitāti angļu valodas vārdkopu mācīšanā. Eksperimentālie rezultāti parādīja, ka tā grupa, kura tika mācīta, izmantojot mobilas ierīces, sasniedza labākus rezultātus nekā tā grupa, kurā tika izmantoti ar tehnoloģijām nesaistīti vārdu krājuma mācīšanas līdzekļi. Tiek secināts, ka mobilo ierīču lietojums angļu vārdkopu mācīšanā ir effektīvā un ilgtspējīgā pieeja, lai veicinātu vārdu krājuma apguves prasmi.Technology is constantly altering the educational environment as well as learning and teaching experience. Therefore, it is only natural that the usage of mobile devices in language education has become a widespread trend nowadays. Despite it, only few studies have explored the application of mobile technology in TEFL in Latvia. The current study aimed to examine whether mobile technology has the potential to promote English vocabulary learning, more specifically the acquisition of collocations. For that purpose, the necessary data was collected on the effectiveness of using mobile devices and non-technological means for teaching English collocations. Experimental results revealed that the group that was taught using mobile devices achieved more substantive results than the group, in which non-technological means for teaching collocations were applied. It was concluded that utilizing mobile devices to learn English collocations is an effective and sustainable approach of facilitating vocabulary acquisition skill

Geospace Environment Modeling 2008-2009 Challenge: Ground Magnetic Field Perturbations

Acquiring quantitative metrics!based knowledge about the performance of various space physics modeling approaches is central for the space weather community. Quantification of the performance helps the users of the modeling products to better understand the capabilities of the models and to choose the approach that best suits their specific needs. Further, metrics!based analyses are important for addressing the differences between various modeling approaches and for measuring and guiding the progress in the field. In this paper, the metrics!based results of the ground magnetic field perturbation part of the Geospace Environment Modeling 2008 2009 Challenge are reported. Predictions made by 14 different models, including an ensemble model, are compared to geomagnetic observatory recordings from 12 different northern hemispheric locations. Five different metrics are used to quantify the model performances for four storm events. It is shown that the ranking of the models is strongly dependent on the type of metric used to evaluate the model performance. None of the models rank near or at the top systematically for all used metrics. Consequently, one cannot pick the absolute winner : the choice for the best model depends on the characteristics of the signal one is interested in. Model performances vary also from event to event. This is particularly clear for root!mean!square difference and utility metric!based analyses. Further, analyses indicate that for some of the models, increasing the global magnetohydrodynamic model spatial resolution and the inclusion of the ring current dynamics improve the models capability to generate more realistic ground magnetic field fluctuations