Man har sedan länge förstått att lärande gynnas repetition och pauser däremellan, menvarför detta har en positiv effekt på långtidsminnet har varit okänt. Försök på råttor harvisat att repetition är viktigt för att förstärka kommunikationen vid synapser som ärviktiga för minnesbildning och att pauser är nödvändiga för att de proteiner som stärkersynapsen ska hinna bildas och verka.Med stöd i detta har man utvecklat en undervisningsteknik som kallas spaced learning,där undervisningsmaterialet presenteras tre gånger, separerat av pauser inkluderande enorelaterad aktivitet. Studier där denna teknik har testats på elever har visat att teknikenhar god effekt på elevernas kunskap, utvärderat med flervalsfrågor, jämfört medkontrollgruppens undervisning och att tekniken lämpar sig väl för att sammanfatta faktaefter en kurs inför prov.Eftersom metoden är relativt ny är mängden och fullständigheten av insamlade data omspaced learnings effekt begränsad. De resultat som finns baseras framförallt påhögstadieelever i England och utvärderingen grundar sig på flervalsfrågor, vilket gör detsvårt att mäta analytiska förmågor.Den mindre studie som presenteras i detta arbete skiljer sig från tidigare studier genomatt eleverna är äldre. I försöket analyseras gymnasieelever till skillnad frånhögstadieelever vilket endast undersökts tidigare i en mindre svensk studie. Ingen av detidigare studierna har heller använt samma undervisande lärare och samma elever, vilketeventuellt kan påverka resultatet. Studien syftar också även till att mäta mer analytiskaförmågor hos eleverna genom att efterfråga förklaringar och motiveringar iprovfrågorna.Resultaten från denna mindre studie antyder att spaced learning ökar elevernaskunskaper, både angående enkla faktakunskaper och mer analyserande kunskaper, påkort sikt. När längre tid har passerat så tycks den procentuella minskningen avprovresultaten vara lika stor oavsett om spaced learning eller traditionell undervisninghar används. Spaced learning fungerade väl i klassrummet och de elever som uttalade sigom metoden uppskattade upplägget.

This study investigates the effect of elaborate retrieval, which is a byproduct of spaced practice, on adult cognition. It was hypothesized that elaborate re-conceptualization of new information, within a context that was disparate from the one used during learning, could facilitate learning transfer through the development of a broader conceptual frame of reference. The re-conceptualization task was not expected to degrade rote definitional memory. The two re-conceptualization tasks used in this study were termed model-building and free study. The model building task required the development of a personalized conceptual model using information provided within three spaced narrated information passages. The free study task required the unaided study of all three passages. Transfer of learning and rote memory were evaluated using a general knowledge test and a knowledge extension test. These tests were given at the end of the experiment. The general knowledge test required participants to match concept labels and definitions which were provided during the experiment. The knowledge extension test required participants to transfer knowledge amassed during the experiment to a complex “real world” situation. The results demonstrated that learners, who completed the spaced re-conceptualization task, improved their ability to transfer new information as the spacing intervals lengthened. Participants who were required to study the same information without any instruction did not show learning transfer improvement. Both groups illustrated parallel improvements in rote memorization due to spacing. / Thesis (Master, Education) -- Queen's University, 2007-12-19 09:35:45.095

When antennas are placed closely spaced together, the mutual coupling and spatial correlation effects undermine the advantages provided by multiple input and multiple output (MIMO) antennas. In this thesis, we compare and analyze the performance of digital beamforming, fixed radio frequency (RF) beamforming and element based patterning with closely spaced antenna systems. In the case where only one RF-chain is available, we have demonstrated performance improvements using RF beamforming-based MIMO processing instead of element-based MIMO processing with closely spaced metamaterial antennas. The result indicates that even without mutual coupling, antenna based MIMO processing is greatly impacted when moving from rich to correlated scattering environments. In the second half of the thesis, we investigate the switch and examine receiver combining (SEC) technique. We derive the switching rate of SEC and show that even though it has the same outage probability as traditional selection combining, it has a significantly lower switching rate.

When antennas are placed closely spaced together, the mutual coupling and spatial correlation effects undermine the advantages provided by multiple input and multiple output (MIMO) antennas. In this thesis, we compare and analyze the performance of digital beamforming, fixed radio frequency (RF) beamforming and element based patterning with closely spaced antenna systems. In the case where only one RF-chain is available, we have demonstrated performance improvements using RF beamforming-based MIMO processing instead of element-based MIMO processing with closely spaced metamaterial antennas. The result indicates that even without mutual coupling, antenna based MIMO processing is greatly impacted when moving from rich to correlated scattering environments. In the second half of the thesis, we investigate the switch and examine receiver combining (SEC) technique. We derive the switching rate of SEC and show that even though it has the same outage probability as traditional selection combining, it has a significantly lower switching rate.

No description available.

The cooling problem has become a serious subject in order to keep away from malfunctioning for a high performance and miniaturized electronic component. For instance, the monitor backlight LED must be cooled adequately. In this thesis, a natural convection cooling problem for the vertical channel with equally spaced heating blocks on one wall is studied by a numerical modeling to simulate a monitor backlight LED cooling. A control volume method is employed for the numerical modeling. The results of heat transfer coefficients and hot spots for various channel gap, LED spacing and Rayleigh number are presented. This study can provide design reference for related cooling problems.

Nya kunskaper om hur hjärnan fungerar när långtidsminnen bildas ligger till grund för undervisningsmetoden spaced learning. Metoden utvecklades i Storbritannien i samarbete mellan lärare, hjärnforskare och socionomer och går ut på att inlärning sker i tre korta, intensiva block separerade av två tydliga pauser om 10 minuter då eleverna får göra en distraherande aktivitet som att rita, arbeta med lera eller jonglera. Just dessa pauser anses kritiska för bildning av långtidsminnen. I denna studie testades metoden inom biologiundervisning med ett slumpmässigt urval elever i en gymnasieklass. Elevernas minnen av de fakta som presenterades under lektionen kvantifierades i ett test 7 dagar efter testlektionen. Antalet poäng på minnestestet jämfördes med en population elever från samma klass som istället för spaced learning fått en lektion med en sammanhängande, mer traditionell, genomgång av samma fakta. Resultatet visar att elever som tillägnat sig kunskaperna i formatet spaced learning har signifikant högre poäng på minnestestet efter 7 dagar, vilket tyder på att dessa elever har fått fler långtidsminnen från undervisningen. Strategier i undervisningen som gör att eleverna minns det de lär sig sparar både tid och resurser i skolan och gör att elevernas kunskaper blir mer varaktiga.

No description available.

Fourier analysis, Walsh-Fourier analysis, and wavelet analysis have often been used in time series analysis. Fourier analysis can be used to detect periodic components that have sinusoidal shape; however, it might be misleading when the periodic components are not sinusoidal. Walsh-Fourier analysis is suitable for revealing the rectangular trends of time series. The flaw of the Walsh-Fourier analysis is that Walsh functions are not periodic. The resulting Walsh-Fourier analysis is more difficult to interpret than classical Fourier analysis. Wavelet analysis is very useful in analyzing and describing time series with gradual frequency changes. Wavelet analysis also has a shortcoming by giving no exact meaning to the concept of frequency because wavelets are not periodic functions. In addition, all three analysis methods above require equally-spaced time series observations. In this dissertation, by using a sequence of periodic step functions, a new analysis method, adaptive Fourier analysis, and its theory are developed. These can be applied to time series data where patterns may take general periodic shapes that include sinusoids as special cases. Most importantly, the resulting adaptive Fourier analysis does not require equally-spaced time series observations. / Ph. D.

Blind equalization schemes are used to cancel the effects of a channel on the received signal when the transmission of a training sequence in a predefined time slot is not possible. In the absence of a training sequence, blind equalization schemes can also increase the throughput of the overall system. A general problem with blind adaptation techniques is that they have poor convergence properties compared to the traditional techniques using training sequences. Having a multi-modal cost surface, blind adaptation techniques may force the equalizer to converge to a false minimum, depending on the initialization. The most commonly used blind adaptation algorithm is the Constant Modulus Algorithm (CMA). It is shown by simulation that a logarithmic error equation can make CMA converge to a global minimum, if a differential encoding scheme is used. The performance of CMA with different error equations is also investigated for different channel conditions. For a time varying channel, the performance of an equalizer not only depends on the convergence behavior but also on the tracking property, which indicates the ability of an equalizer to track changes in the channel. The tracking property of a blind equalizer with CMA has been investigated under different channel conditions. It is also shown that the tracking property of a blind equalizer can be improved by using a recursive linear predictor at the output of the equalizer to predict the amplitude of the equalizer output. The predicted value of the amplitude is then used to adjust the instantaneous gain of the overall system. A recursive linear predictor is designed to predict a colored signal without having a priori knowledge about the correlation function of the input sequence. The performance of the designed predictor is also investigated by predicting the envelope of a flat fading channel under constant mobile velocity and constant acceleration conditions. / Master of Science