Time series prediction for algorithmic rescaling in the cloud

The main goal of this thesis is to predict the number of players in some instance of DICE’s gaming platforms, e.g. Battlefield 3 for PC, 15 minutes in the future. This prediction may be used by the company when buying on-demand cloud servers to tell them how much they need to buy. Several different prediction models are examined and evaluated on historical data from 2011 to 2015. Another focus point is how to detect and handle outliers. The thesis also tries to create a general understanding of player behaviour by using different data separations and statistical methods. From the company’s perspective an auto regressive model of order 100 produces the best result. It is shown that with this model it would be beneficial for the company to use cloud servers instead of physical servers if their mean abundance in server capacity with physical servers is greater than 4134 players. The work was conducted primarily at DICE (EA Digital Illusions CE AB ) in Stockholm from 2015-09-07 to 2016-01-29.Huvudsyftet med denna rapport är att förutsäga antalet spelare i nå- gon instans av DICE: s spelplattformar, t.ex. Battlefield 3 för PC, 15 minuter i framtiden. Denna förutsägelse kan användas av företaget vid köp av molnservrar on-demand för att visa dem hur mycket de behöver köpa. Flera olika prognosmodeller undersöks och utvärderas på historisk data från 2011 till 2015. En annan fokuspunkt är hur man upptäcker och hanterar extremvärden. Rapporten försöker också skapa en allmän förståelse av spelarbeteende genom att separera datan på olika sätt och genom olika statistiska metoder. Från företagets perspektiv ger en autoregressiv modell av ordning 100 det bästa resultatet. Det visar sig att med denna modell skulle det vara fördelaktigt för företaget att använda molnservrar istället för fysiska servrar om deras genomsnittliga överflöd i serverkapacitet med fysiska servrar är större än 4134 spelare. Examensarbetet genomfördes primärt hos DICE (EA Digital Illusions CE AB) i Stockholm från 2015-09-07 till 2016-01-29

EBG enhanced feeds for the improvement of the aperture efficiency of reflector antennas

We describe the use of electromagnetic bandgap (EBG) super-layers to improve the shape of reflectors illumination function. Following an investigation of the leaky wave pole singularities of the EBG Green's function, the shape of the radiation patterns of small apertures in ground planes are optimized. The maximization of the reflector aperture efficiency can be obtained by properly tuning the super layers geometrical parameters. A prototype of such feed has been designed, manufactured and tested. The results indicate that the inclusion of the EBG, increases the aperture efficiency of the feed+reflector system to values higher than 80%, over a 10% bandwidth. These low profile feeds are compatible with printed circuit board and/or integrated technology

Properties of leaky waves supported by grounded dielectric super-layers and implications on the design of reflector feeds

The design strategy that uses dielectric super-layers with neighboring wave-guides closed in matched loads constitutes a worst case scenario as far as the performance enhancement is concerned and finds applicability in radiometric imaging arrays. On the other side the design strategy that uses dielectric super-layers with neighboring wave-guides closed in properly tuned reactive loads can be seen as best case scenario representative of a multi beam system for a telecommunication satellite with independent channels

Kulturmöten sökes!

The object of this essay was to examine the concept of culture and cross culture encounters by studying the group meetings for immigrants at IM, The Swedish Organisation for Individual Relief, in Lund through a cross cultural perspective. The framing questions were: - How can the concept of culture and cross cultural encounters be comprehended and defined? - What does culture and cross cultural encounters signify for the participants of the group meetings. - What impact does culture and cross cultural encounters have on the group meetings. I have tried to outline the discussion on the idea of culture. Through interviews with the participants of the different group meetings on their experiences and views I have found that their perspective in many ways corresponded to what has been said on the subject in the outlined discussion but that culture was not a significant issue at the meetings. Instead the participants emphasised the necessity of learning Swedish and meeting with people regardless of cultural background