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\title{Serverbestimmung für latenzkritische Anwendungen
  in mobilen Ad-hoc Netzen}
\author{Oliver Wellnitz} %\hspace{.75em} Lars Wolf}
\institute[IBR, TU Braunschweig]{IBR\\
	Technische Universität Braunschweig}

\date{16. Juli 2007}

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\begin{document}

\frame{\titlepage} 

\setlength{\iskip}{1em}
\frame{
	\myframetitle{Gliederung}
	\begin{itemize}
	\item Motivation\\[\iskip]
%	\item Mobile Game Cycle \\[\iskip]
	\item Zonen-Server Architektur\\[.3\iskip]
	\begin{itemize}
		\item Algorithmus zur Serverbestimmung \\[.6\iskip]
		\item Dienstgüte\\[\iskip]
	\end{itemize}
	%\item Verwandte Arbeiten\\[\iskip]
	\item Ergebnisse und verwandte Arbeiten\\[\iskip]
	% Ergebnisse und Bewertung
	\item Zusammenfassung und Ausblick\\[\iskip]
	\end{itemize}
}

\mysection{Motivation}
\setlength{\iskip}{.4em}
\frame{
        \myframetitle{Mobile Computer}
        
        %\vspace{-.8cm}
        %\hfill\includegraphics[width=.35\textwidth]{psp.jpg}
 %       \begin{itemize}
 %       		\item PDAs, Mobiltelefone, Notebooks\\[\iskip]
 %       \end{itemize}
 
 		\hspace{5mm}
 		\begin{minipage}[c]{.2\textwidth}
		   \includegraphics[height=3.8cm]{pics/iphone.jpg}
		\end{minipage}
		\begin{minipage}[c]{.35\textwidth}
		   \includegraphics[height=4cm]{pics/dell.jpg}
		\end{minipage}
	        \hspace{.05\textwidth}
		\begin{minipage}[c]{.3\textwidth}
		   \includegraphics[height=4.1cm]{pics/palm.jpg}
		\end{minipage}
		   \hspace{-.05\textwidth}
		   %\hfill
		   %\hspace{.05\textwidth}
 		
		
%        \visible<3->{
%	        \hspace{.15\textwidth}
%		\begin{minipage}[c]{.15\textwidth}
%		   \includegraphics[height=2.1cm]{pics/palm.jpg}
%		\end{minipage}
%		   %\hspace{.05\textwidth}
%		\begin{minipage}[c]{.1\textwidth}
%		   \includegraphics[height=1.8cm]{pics/iphone.jpg}
%		\end{minipage}
%		   %\hfill
%		   %\hspace{.05\textwidth}
%		\begin{minipage}[c]{.15\textwidth}
%		   \includegraphics[height=2cm]{pics/dell.jpg}
%		\end{minipage}
%}

       \begin{itemize}
        \item Deutlicher Trend weg von Desktops hin zu mobilen Geräten\\[.1\iskip]

%	\end{minipage}
%	\hfill
%	\begin{minipage}[b]{.20\textwidth}
%	   \includegraphics[width=\textwidth]{states2-marking.pdf}
%	   \vspace{3cm}
%	\end{minipage}

        \item Mobile Geräte für anspruchsvolle Anwendungen benutzbar\\[\iskip]
        \item Kommunikation nach außen geschieht dabei drahtlos\\[.1\iskip]
        \begin{itemize}
        		\item GSM, UMTS, WLAN
%        		\item GSM: GPRS, EDGE\\[\iskip]
 %       		\item UMTS: HSDPA\\[\iskip]
  %      		\item WLAN: IEEE 802.11a/b/g\\[\iskip]
%		\item Meist zelluläre und infrastrukturbasierte Kommunikation\\[\iskip]
        \end{itemize}
        \end{itemize}
        
%        \only<4->{
%        \vspace{.5em}
%	\begin{center}
%        {\bf Ziel: Überall und jederzeit zu kommunizieren}
%	\end{center}
%	}
}


\setlength{\iskip}{.3em}
\frame{
        \only<1>{
        	\myframetitle{Infrastrukturnetze}
	}
        \only<2->{
        	\myframetitle{Mobile Ad-hoc Netze (MANET)}
	}
        
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%\begin{pspicture}(1,2)
%     \psline{->}(0,0)(1,2)
%\end{pspicture}
%\end{pdfpic}

	\vspace{-4mm}

	\begin{center}
        \only<1>{
		\includegraphics[width=.9\textwidth]{test2/manet3-infrastruktur.pdf}
	}
        \only<2>{
		\includegraphics[width=.9\textwidth]{test2/manet3-p2p.pdf}
	}
        \only<3>{
		\includegraphics[width=.9\textwidth]{test2/manet3-multihop.pdf}
	}

	\end{center}
	%\vspace{-7cm}

        
%        \begin{center}
%        {\large Aufbauendes Bild (Alleine, 2 direkt, kooperativ multihop, +infrastruktur) -> Ein Bild!}
%	\end{center}

 \visible<2->{
	\begin{block}{Idee}
	\hspace{2em}{\sl Benutzer können \alert{überall} und \alert{jederzeit} kommunizieren}
	\end{block}
}

 \visible<2->{
	\begin{block}{Ansatz}	
	\begin{itemize}
\visible<2->{
		\item Direkte Kommunikation zwischen den Geräten
}
%		\begin{itemize}
%			\item No infrastructure needed, no communication costs \\[1.1\iskip]
%		\end{itemize}
\visible<3->{
		\item Kooperatives Weiterleiten von Daten (Multi-Hop)
}
%		\item Infrastrukturnetze können zusätzlich genutzt werden
% XXX TODO: Soll Infrastruktur hier überhaupt erwähnt werden? Eher nein, da nicht Inhalt des Vortrages!
%		\item 3. Punkt
		
	\end{itemize}
	\end{block}
}
}



\setlength{\iskip}{.3em}
\frame{
        \myframetitle{Mehrparteienspiele}
 
 	\vspace{-.70cm}
  %        \begin{block}{Opportunities}
        \begin{itemize}
         \item Computer- und Videospiele sind ein großer Markt\\[.1\iskip]
         \begin{itemize}
         	\item Umsatz von 1,13 Milliarden Euro in 2006 (+7,4\,\%)\\[\iskip]
		\item Spielesoftware für Handhelds legte um 58\,\% zu\\[\iskip]
         \end{itemize}
         
          \item Verschiedene Spielekategorien:\\[.1\iskip]
          \begin{itemize}
              \item Direkte Kontrolle über die Spielfigur\\[.1\iskip]
              \begin{itemize}
              \item Autorennspiele,  Shooter\\[\iskip]
              \end{itemize}
              \item Indirekte Kontrolle über die Spielfigur\\[.1\iskip]
              \begin{itemize}
              \item Strategiespiele\\[\iskip]
              \end{itemize}
              \item Rundenbasierte Spiele\\[.1\iskip]
              \begin{itemize}
              \item Rollenspiele, Kartenspiele, MMORPGs\\[\iskip]
              \end{itemize}
          \end{itemize}

       \vspace{-3.2cm}
       \begin{flushright}
       \hspace{1cm}\includegraphics[width=.33\textwidth]{pics/psp.jpg}
%       \hspace{64mm}\includegraphics[width=.35\textwidth]{pics/psp.jpg}
       \end{flushright}       

%        \end{itemize}
  %      \end{block}
        
%        \vspace{-1em}
        
%        \begin{block}{Challenges}
 %       \begin{itemize}
%       \item Existing games can be split up into different classes \\[.1\iskip]
%        \begin{itemize}
%        \item FPS and simulations have realtime network requirements\\[\iskip]
%        \item RTS and some sports games can deal with higher latency\\[\iskip]
%        \item RPG, Trivia games are mainly round-based thus less demanding\\[\iskip]
%        \item MMOPG, mostly round-based, scalability is an issue\\[\iskip]
%        \end{itemize}
        \end{itemize}
        
        
%          \item Energy Efficiency / Power consumption
 %         \begin{itemize}
  %          \item Think Dell XPS ($\ge$130\,W) % Maxes out its power supply at 130W
%            %\item gaga
%          \end{itemize}
%          \item Communication
%          \begin{itemize}
%            \item Infrastructure availability and costs
%            \item Radio network problems (shared medium and interferences)
%          \end{itemize}
%        \end{itemize}   
%        \end{block}
}

\setlength{\iskip}{.4em}
\frame{
        \myframetitle{Netzanforderungen von Mehrparteienspiele}
        
        \begin{table}
\begin{center}

\setlength\doublerulesep{.5pt}\doublerulesepcolor{white} 
\setlength\arrayrulewidth{2pt}\arrayrulecolor{white} 

\begin{tabular}{>{\columncolor[gray]{.70}[.80\tabcolsep]}l
>{\columncolor[gray]{.85}[.80\tabcolsep]}c
%@{\extracolsep{\fill}}
>{\columncolor[gray]{.70}[.80\tabcolsep]}c
%@{\extracolsep{\fill}}
>{\columncolor[gray]{.85}[.80\tabcolsep]}c
%@{\extracolsep{\fill}}
>{\columncolor[gray]{.70}[.80\tabcolsep]}c}
%\hline

{\bf Spielekategorie }  & {\bf Verzögerung} & {\bf Jitter} & {\bf Paketverlust}  \\ \hline \hline
%\arrayrulecolor{white} 
Direkte Kontrolle    &  150\,ms & hoch & 3 -- 5\,\% \\ \hline 
%\multicolumn{2}{ll}{bsp. & Direkte Kontrolle}    & < 50 -- 150\,ms & +\,/\,-- & < 5\,\% \\ \hline 
Indirekt kontrolliert  &  500\,ms & mittel &  5\,\% \\ \hline 
Rundenbasiert           & >500\,ms & niedrig & N/A \\ \hline
\end{tabular}
\end{center}
%\caption{Network requirements of multi-player games}
\end{table}

\begin{itemize}
\item Alle Werte sind Maximalwerte
\item Datenrate in allen Kategorien insgesamt gering
\begin{itemize}
	\item Typisch $<$ 10 kByte/s 
\end{itemize}
\item Anforderungen an Latenz und Paketverlust können in mobilen ad-hoc Netzen nicht erfüllt werden
\end{itemize}

%\begin{tabular}{lllll}
%{\bf Spieltyp } & {\bf Datenrate} & {\bf Verzögerung} & {\bf Jitter} & {\bf Paketverlust}  \\
%Direkte Kontrolle    & 35\,kBit/s & 50 -- 150\,ms & ++\,/\,+ & 3 -- 5\,\% \\ 
%Indirekt kontrolliert  & 5\,kBit/s & o & o\,/\,-- & o \\ 
%Rundenbasiert           & -- & -- & -- & N/A \\
%\end{tabular}

}

\setlength{\iskip}{.4em}
\frame{
        \myframetitle{Forschungsziel}
        
        \begin{block}{Zielsetzung}
        		\hspace{2em} Aktuelle Mehrparteienspiele in mobilen Ad-hoc Netzen\\
		\hspace{2em} spielbar zu machen
        \end{block}
        
        \begin{block}{Aufgaben}
        \begin{itemize}
        		\item Aufbau einer Sever-Infrastruktur für mobile Mehrparteienspiele\\[-.3em]
		\begin{itemize}
			\item Redundanz
			\item Mobilitätsunterstützung
			\item Skalierbarkeit \& geringen Overhead durch Verwaltung
		\end{itemize}
		\item Einhaltung von Dienstgütekriterien 
		\begin{itemize}
			\item Datenkommunikation soll Spielfluss nicht negativ beeinflussen
		\end{itemize}
        \end{itemize}
        \end{block}
}



%\mysection{Architektur}
\mysection{Serverbestimmung}
\frame{
	\myframetitle{Die Zonen-Server Architektur}

	\begin{itemize}
	\item Klassische Client/Server-Architektur ungeeignet für MANETs\\[\iskip]
%	\item Traditional single game servers are single points of failure
%	\item Fully distributed architectures may have problems with 
%	\begin{itemize}
%	\item Available bandwidth in mobile networks
%	\item Cheating \& Control of the game
%	\end{itemize}
%	\end{itemize}
%	\item Ansatz: Cluster-Head / Super Peer
%	\begin{itemize}
	\item Räumliche Aufteilung des Netzes, ein Server pro Bereich\\[\iskip]
	\item Geringer Abstand zwischen Spieler und Server gewährleistet geringe Latenz \\[\iskip]
	\item Synchronisation zwischen den verschiedenen Servern\\[.1\iskip] %liegt auf nicht-kritischem Pfad 
	\begin{itemize}
	\item Liegt auf nicht-kritischem Pfad \\[\iskip]
	\item Ber\"ucksichtigung des Bereichs von Interesse (area of interest)\\[\iskip]
	\item Zonen-Server können Spieledaten verz\"ogern und/oder zusammenfassen\\[\iskip]
	\end{itemize}
	\item Mischung zwischen Client/Server und P2P Architektur\\[\iskip]
%	\end{itemize}
%	\item Problem:
%	\begin{itemize}
%	   \item How many servers do we need? %(Scenario-dependant)
%	   \item Which mobile nodes should be chosen?
%	   \item $\rightarrow$ Need for server determination algorithm
%	\end{itemize}
	\end{itemize}
}



\setlength{\iskip}{.3em}
\frame{
	\myframetitle{Serverbestimmung}
	%\hspace{5mm}\includegraphics[width=.6\textwidth]{pics/phases-pre.pdf}
	
	   \begin{itemize}
	   \item Welche Spieler sollen die Rolle eines Servers übernehmen?\\[\iskip]
	   \item Bevorzugt werden Spieler mit\\[.1\iskip]
	   \begin{itemize}
	   	\item leistungsfähigen Geräten (Geräteindex)\\[\iskip]
		\item zentraler Position im Netz\\[\iskip]
	   \end{itemize}
	  % \item We proposed an algorithm that determines dominating set of players\\[\iskip]
	   \end{itemize}
	   
	   \vspace{-1em}
	   % Ergebnisse von Edgar!
	   %\hspace{7mm}\includegraphics[width=.8\textwidth]{pics/serverselection.pdf}
	   \begin{center}
	   	\includegraphics[width=\textwidth]{test2/serverselection-ueberleitung.pdf}
	   \end{center}
}


\frame{
        \only<1>{
	   \myframetitle{Beispiel: Serverbestimmung (1/4)}
	}
        \only<2>{
	   \myframetitle{Beispiel: Serverbestimmung (2/4)}
	}
        \only<3>{
	   \myframetitle{Beispiel: Serverbestimmung (3/4)}
	}
        \only<4>{
	   \myframetitle{Beispiel: Serverbestimmung (4/4)}
	}

%	\begin{minipage}[b][5cm][s]{.78\textwidth}
%	\begin{minipage}[b][4cm][s]{\textwidth}
%	\only<1>{
%	\begin{block}{Description}
%	\begin{itemize}
%	   \item Dominating set algorithm
%	   \item It comprises mainly 3~phases
%	   \begin{itemize}
%	      \item Discovery Phase
%	      \item Determination Phase
%	      \item Marking Phase
%	   \end{itemize}
%	   \item Mobility Management during the game
%	\end{itemize}
%	\end{block}
%	}
%	\only<2>{
%	\begin{block}{Discovery Phase}
%	\begin{itemize}
%	\item Determine available resources (weight)
%	\begin{itemize}
%	\item May include CPU, RAM, battery, \ldots
%		\end{itemize}
%	\item Determine number of neighbours (degree)
%		\item Start periodically broadcasting this information to
%		neighbouring nodes
%		\item Build neighbour list based on received info
%		\end{itemize}
%	\end{block}
%	}
%	\only<3>{
%	\begin{block}{Determination Phase}
%	\begin{itemize}
%	\item Sort neighbour list 
%		\begin{itemize}
%	\item Order by weight, degree, node~ID
%		\end{itemize}
%	\item Calculate best server 
%		\begin{itemize}
%	\item First node on neighbour list with degree~$>~1$
%		\end{itemize} 
%	\item Send ticket to best server
%		\end{itemize}
%	\end{block}
%	}
%	\only<4>{
%	\begin{block}{Marking Phase}
%	\begin{itemize}
%	\item Set tag
%		\begin{itemize}
%	\item Server, Server neighbour, or Empty tag
%		\end{itemize}
%	\item Add tag to the information broadcasted to neighbours
%	\end{itemize}
%	\end{block}
%	}
%	\only<5>{
%	\begin{block}{During the game}
%	\begin{itemize}
%	\item Continuous updates
%	\begin{itemize}
%	  \item Create new servers
%	  \item Degrade servers back to players
%	  \item Can be integrated in game protocol itself
%	\end{itemize}
%	\item Mobility may require handoff to a better server
%	\begin{itemize}
%	   \item Decision to be made by the game
%	   \item Threshold-based mechanism is advised
%	\end{itemize}
%	\end{itemize}
%	\end{block}
%	}
%	\end{minipage}
%\vfill
%	\begin{minipage}[b][1cm][s]{\textwidth}
%\vspace{-2mm}
%		\begin{block}{Example}
%		\vspace{-7mm}
\begin{center}
%\only<1>{
%   \includegraphics[width=\textwidth]{pics/network2-plain.pdf}
%}
\only<1>{
   \includegraphics[width=\textwidth]{pics/network2-discovery.pdf}
}
\only<2>{
   \includegraphics[width=\textwidth]{pics/network2-determination.pdf}
}
\only<3>{
   \includegraphics[width=\textwidth]{pics/network2-marking.pdf}
}
\only<4>{
   \includegraphics[width=\textwidth]{pics/network2-game.pdf}
}
%\only<6>{
%   \includegraphics[width=\textwidth]{pics/serverselection_de.pdf}
%}
\end{center}
%\end{block}
%	\end{minipage}
%	\end{minipage}
}


\frame{

	\myframetitle{Eigenschaften des Algorithmus}

	\begin{itemize}
		\item Spieler sind nahe bei einem Server
		\begin{itemize}
			\item Abstand beträgt maximal 2 Schritte (wo möglich)
			\item Algorithmus berechnet die dominierende Menge
			%\item Sync zwischen Server meist nicht zeitkritisch
		\end{itemize}
		\item Skalierbarkeit
		\begin{itemize}
			\item Aufwand $O(n)$, $n \ll N$, 40 Bytes/s/Nachbar
		\end{itemize}
%		\item Phasen
%		\begin{itemize}
%			\item Aufwand O(...)
%		\end{itemize}
		\item Metrik ist Kombination aus
		\begin{itemize}
			\item Fähigkeiten des mobilen Gerätes (Geräteindex)
			\begin{itemize}
				\item Prozessor, Speicher, Energie, \ldots
			\end{itemize}
			\item Anzahl der Verbindungen zu Nachbarknoten
		\end{itemize}
		\item Einschränkungen
		\begin{itemize}
			%\item Geräte sollten den Algorithmus aktiv unterstützen
			\item Unterstützt keine globalen Integritätsbedingungen
		\end{itemize}
		
		\end{itemize}
}


\mysection{Dienstgüte}
\frame{
	\myframetitle{Dienstgüte}

	\begin{itemize}
%		\item Probleme in mobilen ad-hoc Netzen\\[.1\iskip]
%		\begin{itemize}
			\item Probleme bei der drahtlosen Übertragung in MANETs\\[.1\iskip]
				\begin{itemize}
					\item Störungen der Funkübertragung\\[\iskip]
					\item Begrenzte Reichweite des Funksignals\\[\iskip]
					\item Begrenzte Kapazität des Mediums\\[\iskip]				
				\end{itemize}
			\item Mobilität der Benutzer\\[.1\iskip]
			\begin{itemize}
				\item Beeinträchtigt die Übertragung zusätzlich\\[\iskip]
				\item Bewegende Zwischenstationen beeinflussen Verkehr zwischen ortsfesten Geräten\\[\iskip]
			\end{itemize}
%		\end{itemize}
		\item Latenz, Jitter und Paketverluste deutlich höher als im Internet\\[\iskip]
		
%		\item Latency, jitter and loss is higher than in today's Internet\\[\iskip]
%		\item Additional problems due to wireless transmissions and mobility\\[\iskip]
	   %\item Congestion problem\\[\iskip]
%		\item QoS modifications allow for good conditions for up to 3 hops \\[\iskip]
	 \end{itemize}
}


\frame{
	\myframetitle{Dienstgüte für latenzkritische Anwendungen}
	
%	\begin{itemize}
 %       \item Related work shows network requirements for realtime games\\[.1\iskip]
%        \begin{itemize}
%        \item Delays greater than 50--75\,ms are noticeable by players \\[\iskip]
%        \item Upper threshold is game-dependant between 100 and 200\,ms\\[\iskip]
%        \item Jitter and packet loss should be low, depends on game\\[.1\iskip]
%       		 \begin{itemize}
%		\item max. 3 -- 5 \% packet loss is tolerable for most games\\[\iskip]
%		\end{itemize}
%	\item Network requirements depends on latency compensation method  (e.g. dead reckoning) used for a game\\[\iskip]
%	\end{itemize}
%	\item We analyzed several different improvements for MANETs\\[.1\iskip]
	\begin{itemize}
		\item Anpassungen auf Medienzugriffsschicht\\[.1\iskip]
			\begin{itemize}
				\item Stabile Verbindungen, Überwachung der Signalstärke von Nachbargeräten\\[\iskip]
				\item {\color{red}\underline{Entdeckung von Nachbarn}} und verlorenen Verbindungen\\[\iskip]
			\end{itemize}
		\item Anpassungen in der Wegewahl (hier für AODV)\\[.1\iskip]
			\begin{itemize}
				\item Lokales Reparieren von Wegstrecken\\[\iskip]
				\item {\color{red} \underline{Vorhalten redundater Wegstrecken}}\\[\iskip]
			\end{itemize}
		\item Verkehrssteuerung und Priorisierung\\[.1\iskip]
			\begin{itemize}
				\item Prioritätsgesteuertes Versenden beim Weiterleiten\\[\iskip]
				\item {\color{red} \underline{Frühzeitiges Verwerfen von interaktiven Daten}}\\[\iskip]
				\item {\color{red} \underline{Datenratenbeschränkung für nicht-interaktiven Verkehr}}\\[\iskip]
			\end{itemize}
	\end{itemize}
%	\end{itemize}
}


\mysection{Auswertung}
\setlength{\iskip}{.1em}
\frame{
	\myframetitle{Auswertung}
	
	\vspace{-10mm}
	\begin{flushright}
	   \includegraphics[width=.35\textwidth]{pics/DeutscheBahn_gobeirne.jpg}
	\end{flushright}
	\vspace{-25mm}
	
	\begin{block}{Realistische Szenarien}
%		\begin{itemize}
%			\item Realistische Szenarien für Spiele in mobilen Netzen
			\begin{itemize}
				\item Im Bahnhof\\[\iskip]
				\item Im Zug \\[\iskip]
				\item Auf dem Schulhof während der Pause\\[\iskip]
			\end{itemize}
%		\end{itemize}
	\end{block}
	
	\begin{block}{Auswertung}
		\begin{itemize}
			\item Simulation mit NS-2\\[\iskip]
			\item Bestimmung der Simulationsparameter mit Hilfe von\\[.1\iskip]
			\begin{itemize}
				\item Szenarien\\[\iskip]
				\item Realen Messungen\\[\iskip]
			\end{itemize}
		\end{itemize}
	\end{block}
	
	
%	
%	\begin{itemize}
%	\item Why do we need scenarios?\\[.1\iskip]
%		\begin{itemize}
%		\item Not every conceivable scenario is plausible\\[\iskip]
%		\item E.g. you need some free time to spare\\[\iskip]
%		\end{itemize}
%	%\begin{itemize}
%      	\item Scenarios are vital to determine network parameters\\[.1\iskip]
%		\begin{itemize}
%		\item How many mobile devices in the network? How many players?\\[\iskip]
%		\item Do mobile nodes move? How often, how fast?\\[\iskip]
%		\item What is the expected size of the network?\\[\iskip] %What are the network conditions?
%		\end{itemize}
%	%\end{itemize}
%	\item Our scenarios:\\[.1\iskip]
%		\begin{itemize}
%			\item Scenario A: Train Station\\[\iskip]
%			\item Scenario B: Train Ride\\[\iskip]
%			\item Scenario C: School Yard\\[\iskip]
%			\item Scenario D: Mixed reality / Location-based Game\\[\iskip]
%		\end{itemize}
%	\end{itemize}
}


%\frame{
%	\myframetitle{Auswertung -- Serverbestimmung}
%
%	\begin{itemize}
%	\item Implemented server determination algorithm in NS-2
%	\item Two scenarios: (15/35 nodes total with 10/25 players)
%	\begin{itemize}
%	\item School yard ($400 \times 400\,{\sf m}^2$)
%	\begin{itemize}
%	\item Low mobility (2\,m/s max.)
%	\end{itemize}
%	\item Train ($240 \times 5\,{\sf m}^2$)
%	\begin{itemize}
%	\item Low mobility (2\,m/s max.), 50\% of players do not move
%	\item Reduced transmission range (40\,m)
%	\end{itemize}
%	\end{itemize}
%	\item Realistic Game Traffic: 64 bytes CBR @ 20pps
%	\item Background Traffic: 5/15 flows $\times$ 64 bytes CBR @ 10pps
%	\item AODV routing protocol
%	\item Goal for total number of game servers
%	\begin{itemize}
%	\item Redundancy requires a minimum of two servers
%	\item Well-below $N/2$ to allow for traffic reduction between
%	servers
%	\end{itemize}
%	\end{itemize}
%}


\frame{
	\myframetitle{Ergebnisse -- Serverbestimmung}
	
	\begin{center}
 	       \includegraphics[width=.9\textwidth]{pics/evaluation-server+pps.pdf}
	\end{center}
}



\frame{
	\myframetitle{\raisebox{0ex}{Communication}\hspace{19.6mm}\includegraphics[width=.6\textwidth]{/home/wellnitz/doc/conferences/game-on-2006/pics/phases-in.pdf}}
	\myframetitle{Ergebnisse --  Dienstgüte (vorläufig)}
	
	   
	   % Bild: Philipp!
	   % alternativ Bild: AODV oder anders von Dirk Budke
	   \begin{center}
%	   \includegraphics[width=.9\textwidth]{pics/high-priority-combined-impact-loss-rate-hop-count.pdf}
	   \includegraphics[width=\textwidth]{pics/eval-qos.pdf}
	   \end{center}
	   \begin{itemize}
	   \item Nicht rechtzeitig empfangene Pakete gelten als verloren
	   \end{itemize}
}


\frame{
	\myframetitle{Verwandte Arbeiten}

%	\begin{block}{Architekturen}
%		\begin{itemize}
%			\item gaga
%		\end{itemize}
%	\end{block}

	\begin{block}{Verteilte Serverauswahl}
		\begin{itemize}
			\item Priority Based Selection (Farkas, 2006)
			\begin{itemize}
				\item Alle Geräte im Netz können Serverrolle übernehmen
				\item Höhere Anzahl Server bei hoher Spielerzahl
			\end{itemize}
			\item Bestimmung dominierender Mengen 
			\begin{itemize}
				\item Algorithmen aus der Graphentheorie
			\end{itemize}
		\end{itemize}
	\end{block}

	\vspace{-3mm}

	\begin{block}{Dienstgüte}
		\begin{itemize}
			\item Dienstgüteerweiterung für WLAN  (IEEE 802.11e, 2006)
			\begin{itemize}
				\item Erzielt gute Ergebnisse
				\item Betrachtet keinen Datenverkehr über mehrere Geräte hinweg
			\end{itemize} 
			%\item QoS Architekturen: INSIGNIA (2000), FQMM ( , CEDAR, SWAN
			\item Dienstgüte-Architekturen
			\begin{itemize}
				\item CEDAR (INFOCOM'99), SWAN (INFOCOM'02)
			\end{itemize}
		\end{itemize}
	\end{block}


}

%\setlength\doublerulesep{1pt}\doublerulesepcolor{white} 
%\setlength\arrayrulewidth{1pt}\arrayrulecolor{black} 
%\frame{
%	\myframetitle{Vergleich mit verwandten Arbeiten}
%
%	\begin{tabular}{lcccc}
%		%\hline
%		{\bf Verfahren} & {\bf Mobilität} & {\bf 2.Thema} & {\bf 3. Thema}& {\bf 4. Thema}\\ \hline %\hline
%		\hspace{.0em}{\sl Serverbestimmung} \\
%			\hspace{1.25em}Farkas     & X & X & X \\
%			\hspace{1.25em}Wu et.al. &  - & X & - \\ \hline
%		\hspace{.0em}{\sl Dienstgüte}\\
%			\hspace{1.25em}SWAN\\
%			\hspace{1.25em}IEEE 802.11e\\
%	\end{tabular}
%
%
%
%}



\mysection{Zusammenfassung}
\frame{
	\myframetitle{Zusammenfassung}
	%\begin{block}{Summary}
	%\begin{itemize}
	%\item Zone Server architecture for MANET games
	%\item Distributed Game Server Determination
	%\begin{itemize}
	%   \item Dominating set algorithm
	%   \item Scalable approach with low overhead
	%\end{itemize}
	%\item Preliminary evaluation shows promising results
	%\end{itemize}
	%\end{block}
	%\begin{block}{Outlook}
	%\begin{itemize}
	%\item Server synchronisation strategy
	%\begin{itemize}
	%   \item Aggregate/delay/avoid game data between servers
	%\end{itemize}
	%\item Handoff strategy
	%\item Evaluate more realistic scenarios
	%\end{itemize}
	%\end{block}
	\begin{itemize}
	\item Interaktive und latenzkritische Anwendungen sind auch in MANETs möglich\\[\iskip]

	\item Zonen-Server Architektur\\[.1\iskip]
%	\item Distributed Server Determination
	\begin{itemize}
	  \item Server sind verantwortlich f\"ur ihren Bereich des Netzes\\[\iskip]
	 \end{itemize}
	  \item Verteilte Bestimmung von Zonen-Servern\\[.1\iskip]
	\begin{itemize}
%	   \item Dominating set algorithm
	   \item Skalierbarer Ansatz mit geringem Overhead\\[\iskip]
%	   \item Initial evaluation shows good results
	\end{itemize}
	%\item Simulators are necessary for an evaluation
	\item WLAN Verbesserungen erf\"ullen Dienstg\"uteanforderungen \\[.1\iskip]
	\begin{itemize}
		\item Vorschläge für Anpassungen auf verschiedenen Schichten\\[\iskip]
		\item Im Zeitlimit latenzkritischer Anwendungen bis zu drei Schritten\\[\iskip]
	\end{itemize}
	\end{itemize}
}


\setlength{\iskip}{.3em}
\frame{
	\myframetitle{Ausblick}
	
	\begin{itemize}
%		\item Mobiltitätsmanangement
		\item Synchronisation von Servern\\[.1\iskip]
		\begin{itemize}
			\item Inbesondere bei Spielen häufig anwendungsspezifisch\\[\iskip]
		\end{itemize}
		\item Unterstützung neuer Spieleformen\\[.1\iskip]
		\begin{itemize}
			\item Ortsgebundene Spiele\\[\iskip]
			\item Mixed-Reality Spiele\\[\iskip]
		\end{itemize}
		\item Einbeziehung von Infrastrukturnetzen\\[.1\iskip]
		\begin{itemize}
			\item Integration von Internet-basierten Spielen\\[\iskip]
			\item Erweiterung von mobilen ad-hoc Netzen\\[\iskip]
		\end{itemize}
	\end{itemize}
	
}

\frame{
	\begin{center}
	\vspace{1.8cm}
	{\Huge Fragen? Kommentare?}\\[3.5em]
	{\Large \inserttitle}\\[2em]
	%{\Large \inserttitle}\\[.25em]
	%{\insertsubtitle}\\[2em]
	\begin{tabular}{rl}
	%\underline{Oliver Wellnitz} & {\tt $<$wellnitz@ibr.cs.tu-bs.de$>$}\\
	Oliver Wellnitz & {\tt $<$wellnitz@ibr.cs.tu-bs.de$>$}\\
	%Lars Wolf & {\tt $<$wolf@ibr.cs.tu-bs.de$>$}\\
	\end{tabular}
	\end{center}
}

\end{document}
\endinput
\appendix 
\section{\appendixname} 

\frame{
\vfill
\begin{center}
{\Huge Appendix A}\\[1em]
{\large Mobile Game Cycle}
\end{center}
\vfill
}


\setlength{\iskip}{.6em}
\frame{
	\myframetitle{Mobile Game Cycle}
	
	
	\begin{itemize}
	  \item Mobile games have to face different problems than Internet games\\[\iskip]
	  \item The three phases for mobile gaming\\[.2\iskip]
	\begin{itemize}
	  \item Pre-Game -- Game Preparation\\[\iskip]
	  \item In-Game -- Playing the game\\[\iskip]
	  \item Post-Game -- After the game\\[\iskip]
	\end{itemize}
	\item Each game phase has its distinctive challenges\\[\iskip]
	\end{itemize}
	\vspace{-.5ex}
	%\hspace{5mm}\includegraphics[width=.8\textwidth]{pics/phases.pdf}
	\begin{center}
	\includegraphics[width=.8\textwidth]{pics/phases.pdf}
	\end{center}
}


\setlength{\iskip}{.3em}
\frame{
        \myframetitle{\raisebox{0ex}{Player
	Discovery}\hspace{18mm}\includegraphics[width=.6\textwidth]{pics/phases-pre.pdf}}
	%\myframetitle{Creating the Game}
	%\hspace{5mm}\includegraphics[width=.6\textwidth]{pics/phases-pre.pdf}
	
	   \begin{itemize}
	   \item Find players in the neighbourhood\\[\iskip]
	   \item Easy solution: Use existing service discovery mechanisms\\[.1\iskip]
	   \begin{itemize}
	   \item Service Discovery Protocol (RfC 2327, PS)
	   \item Konark, service discovery in MANETs\\[\iskip]
	   \end{itemize}
	   \end{itemize}
	   \begin{itemize}
	   \item Agree on a game to play with other players\\[\iskip]	   
	   \item Use a general mobile gaming browser + chat\\[.1\iskip]
	   \begin{itemize}
	   \item Similar to today's server browsers for a single game
	   \end{itemize}
	   \end{itemize}
}



\setlength{\iskip}{.6em}
\frame{
        \myframetitle{\raisebox{0ex}{Software
	Distribution}\hspace{8.2mm}\includegraphics[width=.6\textwidth]{pics/phases-pre.pdf}}
	%\myframetitle{Creating the Game}
	%\hspace{5mm}\includegraphics[width=.6\textwidth]{pics/phases-pre.pdf}
	

	   \begin{itemize}
	   \item Problem: Game software at players may be disjunct\\[\iskip]
	   \item Allow for software download from other players\\[\iskip]
	   \item But there are licensing problems\\[\iskip]
	   \item Sell multi-player license with the game\\[.1\iskip]
	   \begin{itemize}
	   \item 1 owner license + 5 players licenses\\[\iskip]
	   \end{itemize}
	   \item A game can only be played if the licensee is also in that game\\[\iskip]
	   \end{itemize}

}


\setlength{\iskip}{.3em}
\frame{
        \myframetitle{\raisebox{0ex}{Assigning Game
	Servers}\hspace{2.7mm}\includegraphics[width=.6\textwidth]{pics/phases-pre.pdf}}
	%\myframetitle{Creating the Game}
	%\hspace{5mm}\includegraphics[width=.6\textwidth]{pics/phases-pre.pdf}
	
	   \begin{itemize}
	   \item Find players with ,,strong'' machines at suitable locations\\[\iskip]
	   \item We proposed an algorithm that determines dominating set of players\\[\iskip]
	   \end{itemize}
	   
	   \vspace{-1em}
	   % Ergebnisse von Edgar!
	   \hspace{7mm}\includegraphics[width=.8\textwidth]{pics/serverselection.pdf}

}


\setlength{\iskip}{.5em}
\frame{
	\myframetitle{\raisebox{0ex}{Mobility
	Management}\hspace{6.8mm}\includegraphics[width=.6\textwidth]{pics/phases-in.pdf}}
	%\myframetitle{Playing the Game}

	   \begin{itemize}
	   \item Deal with node movement and radio interferences\\[.1\iskip]
	   \begin{itemize}
	   \item Players, game servers and supporting nodes can move\\[\iskip]
	   \end{itemize}
	   \item Players  handoff to another server during  the game\\[\iskip] % network degradation
	   \item Adjust number and position of game servers if necessary\\[.1\iskip]
	   \begin{itemize}
	   \item Add new game servers\\[\iskip]
	   \item Degrade unused players back to player status\\[\iskip]
	   \end{itemize}
	   %\item Add new game servers, degrade unused servers back to player \\[\iskip]
	    \item Strategies to handle disconnected players\\[.1\iskip]
%	   \begin{itemize}
%	   \item Freeze \& Protect, Let the computer take over (AI player)\\[\iskip]
%	   \item Freeze \& Protect, Let the computer take over (AI player)\\[\iskip]
%	   \end{itemize}

	   
	   



%Node movement and radio interferences
%Handoff players to other servers
%Strategies to handle disconnected players
%- Freeze and Protect
%- Computer tages over (AI player)
%- But Fairness issues

	   \end{itemize}
}


\frame{
	\myframetitle{\raisebox{0ex}{Communication}\hspace{19.6mm}\includegraphics[width=.6\textwidth]{pics/phases-in.pdf}}
	%\myframetitle{Playing the Game}
	
	\begin{itemize}
	   \item Latency, jitter and loss is higher than in today's Internet\\[\iskip]
	   \item Additional problems due to wireless transmissions and mobility\\[\iskip]
	   %\item Congestion problem\\[\iskip]
	   \item QoS modifications allow for good conditions for up to 3 hops \\[\iskip]
	   \end{itemize}
	   
	   % Bild: Philipp!
	   % alternativ Bild: AODV oder anders von Dirk Budke
	   \begin{center}
	   \includegraphics[width=.9\textwidth]{pics/high-priority-combined-impact-loss-rate-hop-count.pdf}
	   \end{center}
}


\frame{
	\myframetitle{\raisebox{0ex}{Game Splits \&
	Merges}\hspace{5.3mm}\includegraphics[width=.6\textwidth]{pics/phases-in.pdf}}
	%\myframetitle{Playing the Game}
	
	   \begin{itemize}
	   \item Detect game splits reliably, timeout-based mechanism\\[.1\iskip]
	   \begin{itemize}
	   \item Timeout-based mechanism\\[\iskip]
	   \end{itemize}
	   \item But can two games also be merged again at a later time?\\[.1\iskip]
	   \begin{itemize}
	   \item Depends on game state, game-dependant decision\\[\iskip]
	   \item Fairness issues\\[\iskip]
	   \end{itemize}
	   %\item xxx\\[\iskip]
	   \end{itemize}
}


\setlength{\iskip}{.6em}
\frame{
       \myframetitle{\raisebox{0ex}{After the
       Game}\hspace{19.8mm}\includegraphics[width=.6\textwidth]{pics/phases-post.pdf}}
	%\myframetitle{After the Game}
        %\hspace{5mm}\includegraphics[width=.6\textwidth]{pics/phases-post.pdf}
	
	\begin{itemize}
	\item Store game results persistently\\[.1\iskip]
	   \begin{itemize}
	   \item E.g. Highscore\\[\iskip]
	    \item Use infrastructure networks\\[\iskip]
	   \end{itemize}
	\item Organise next game\\[.1\iskip]
	   \begin{itemize}
	   \item Play game again, switch to another game\\[\iskip]
	   \item Chat application, VoIP\\[\iskip]
	   \end{itemize}
	%\item Portable MMORPG characters
	\end{itemize}
}





\frame{
\vfill
\begin{center}
{\Huge Appendix B}\\[1em]
{\large The Server Determination Algorithm}
\end{center}
\vfill
}


\section{A-SERVERDETERMINATION}

\frame{
        \only<1>{
	   \myframetitle{Overview of the Algorithm}
	}
        \only<2>{
	   \myframetitle{The Server Determination Algorithm (1/4)}
	}
        \only<3>{
	   \myframetitle{The Server Determination Algorithm (2/4)}
	}
        \only<4>{
	   \myframetitle{The Server Determination Algorithm (3/4)}
	}
        \only<5>{
	   \myframetitle{The Server Determination Algorithm (4/4)}
	}

	\begin{minipage}[b][5cm][s]{.78\textwidth}
	\begin{minipage}[b][4cm][s]{\textwidth}
	\only<1>{
	\begin{block}{Description}
	\begin{itemize}
	   \item Dominating set algorithm
	   \item It comprises mainly 3~phases
	   \begin{itemize}
	      \item Discovery Phase
	      \item Determination Phase
	      \item Marking Phase
	   \end{itemize}
	   \item Mobility Management during the game
	\end{itemize}
	\end{block}
	}
	\only<2>{
	\begin{block}{Discovery Phase}
	\begin{itemize}
	\item Determine available resources (weight)
	\begin{itemize}
	\item May include CPU, RAM, battery, \ldots
		\end{itemize}
	\item Determine number of neighbours (degree)
		\item Start periodically broadcasting this information to
		neighbouring nodes
		\item Build neighbour list based on received info
		\end{itemize}
	\end{block}
	}
	\only<3>{
	\begin{block}{Determination Phase}
	\begin{itemize}
	\item Sort neighbour list 
		\begin{itemize}
	\item Order by weight, degree, node~ID
		\end{itemize}
	\item Calculate best server 
		\begin{itemize}
	\item First node on neighbour list with degree~$>~1$
		\end{itemize} 
	\item Send ticket to best server
		\end{itemize}
	\end{block}
	}
	\only<4>{
	\begin{block}{Marking Phase}
	\begin{itemize}
	\item Set tag
		\begin{itemize}
	\item Server, Server neighbour, or Empty tag
		\end{itemize}
	\item Add tag to the information broadcasted to neighbours
	\end{itemize}
	\end{block}
	}
	\only<5>{
	\begin{block}{During the game}
	\begin{itemize}
	\item Continuous updates
	\begin{itemize}
	  \item Create new servers
	  \item Degrade servers back to players
	  \item Can be integrated in game protocol itself
	\end{itemize}
	\item Mobility may require handoff to a better server
	\begin{itemize}
	   \item Decision to be made by the game
	   \item Threshold-based mechanism is advised
	\end{itemize}
	\end{itemize}
	\end{block}
	}
	\end{minipage}
\vfill
	\begin{minipage}[b][1cm][s]{\textwidth}
%\vspace{-2mm}
		\begin{block}{Example}
		\vspace{-7mm}
\begin{center}
\only<1>{
   \includegraphics[width=\textwidth]{pics/network2-plain.pdf}
}
\only<2>{
   \includegraphics[width=\textwidth]{pics/network2-discovery.pdf}
}
\only<3>{
   \includegraphics[width=\textwidth]{pics/network2-determination.pdf}
}
\only<4>{
   \includegraphics[width=\textwidth]{pics/network2-marking.pdf}
}
\only<5>{
   \includegraphics[width=\textwidth]{pics/network2-game.pdf}
}
\end{center}
\end{block}
	\end{minipage}
	\end{minipage}
	\hfill
		\begin{minipage}[t][5cm][b]{.2\textwidth}
           %\vspace{-80mm}
	   \only<1>{
		\includegraphics[width=\textwidth]{pics/states2-plain.pdf}
	   }
	   \only<2>{
		\includegraphics[width=\textwidth]{pics/states2-discovery.pdf}
	   }
	   \only<3>{
		\includegraphics[width=\textwidth]{pics/states2-determination.pdf}
	   }
	   \only<4>{
	   \includegraphics[width=\textwidth]{pics/states2-marking.pdf}
	   }
	   \only<5>{
	   \includegraphics[width=\textwidth]{pics/states2-game.pdf}
	   }
	   \vspace{55mm}
	\end{minipage}
}


%\begin{colormixin}{35!averagebackgroundcolor}
%\end{colormixin}

%\mysection{Sever Selection}
%\setlength{\iskip}{.2em}
%\frame{
%	\myframetitle{Game Server Selection}
%	\begin{itemize}
%	\item Information from Server Determination Algorithm can also be
%	used to assist server selection\\[\iskip]
%	\item Nodes with Server/Server neighbour tag\\[\iskip]
%	\begin{itemize}
%	\item Already know their server\\[\iskip]
%	\end{itemize}
%	\item Nodes with Empty tag\\[\iskip]
%	\begin{itemize}
%	\item If available: Ask neighbouring node with Server Neighbour tag \\[\iskip]
%	\item Otherwise: Use service discovery mechanism\\[\iskip]
%	\end{itemize}
%	\end{itemize}
%}




%\frame{
%	\myframetitle{Overhead}
%	\begin{itemize}
%	\item Overhead of Server Determination Algorithm at Network Layer
%	$$ ({\sf player\_neighbours}_{n_0}+1) \times {\sf 20\,
%	bytes} \times f$$
%	with $f=1 / 2s$
%	\item Overhead is $O(n)$
%	\item But data remains in broadcast domain (local send)
%	\begin{itemize}
%	\item So $n \le\,\, \#\,\, {\sf\,\, neighbouring\,\, nodes}$
%	\end{itemize}
%	\end{itemize}
%}


\frame{
	\myframetitle{Evaluation Setup}
	\begin{itemize}
	\item Implemented server determination algorithm in NS-2
	\item Two scenarios: (15/35 nodes total with 10/25 players)
	\begin{itemize}
	\item School yard ($400 \times 400\,{\sf m}^2$)
	\begin{itemize}
	\item Low mobility (2\,m/s max.)
	\end{itemize}
	\item Train ($240 \times 5\,{\sf m}^2$)
	\begin{itemize}
	\item Low mobility (2\,m/s max.), 50\% of players do not move
	\item Reduced transmission range (40\,m)
	\end{itemize}
	\end{itemize}
	\item Realistic Game Traffic: 64 bytes CBR @ 20pps
	\item Background Traffic: 5/15 flows $\times$ 64 bytes CBR @ 10pps
	\item AODV routing protocol
	\item Goal for total number of game servers
	\begin{itemize}
	\item Redundancy requires a minimum of two servers
	\item Well-below $N/2$ to allow for traffic reduction between
	servers
	\end{itemize}
	\end{itemize}
}

\frame{
	\myframetitle{Evaluation: No. of Game Servers at Game Start}
        \includegraphics[width=.8\textwidth]{pics/evaluation-beginning1.pdf}
        %\includegraphics[width=\textwidth]{final1.pdf}
	%\begin{itemize}
	%\end{itemize}
}

\frame{
	\myframetitle{Evaluation: Game Servers at Game Start (v1\&2)}
        \includegraphics[width=.8\textwidth]{pics/evaluation-beginning-all.pdf}
}

\frame{
	\myframetitle{Evaluation: Players per Game Server}
        \includegraphics[width=.8\textwidth]{pics/evaluation-pps-beginning.pdf}
        %\includegraphics[width=\textwidth]{final2.pdf}
}


\frame{
\vfill
\begin{center}
{\Huge Appendix C}\\[1em]
{\large Scenarios}
\end{center}
\vfill
}




\setlength{\iskip}{.1em}
\frame{
	\myframetitle{Mobile Gaming Scenarios}
	
	\begin{itemize}
	\item Why do we need scenarios?\\[.1\iskip]
		\begin{itemize}
		\item Not every conceivable scenario is plausible\\[\iskip]
		\item E.g. you need some free time to spare\\[\iskip]
		\end{itemize}
	%\begin{itemize}
      	\item Scenarios are vital to determine network parameters\\[.1\iskip]
		\begin{itemize}
		\item How many mobile devices in the network? How many players?\\[\iskip]
		\item Do mobile nodes move? How often, how fast?\\[\iskip]
		\item What is the expected size of the network?\\[\iskip] %What are the network conditions?
		\end{itemize}
	%\end{itemize}
	\item Our scenarios:\\[.1\iskip]
		\begin{itemize}
			\item Scenario A: Train Station\\[\iskip]
			\item Scenario B: Train Ride\\[\iskip]
			\item Scenario C: School Yard\\[\iskip]
			\item Scenario D: Mixed reality / Location-based Game\\[\iskip]
		\end{itemize}
	\end{itemize}
	
	%\hspace{-19mm}\includegraphics[width=.4\textwidth]{pics/DeutscheBahn_gobeirne.pdf}\hspace{1mm}\includegraphics[width=.4\textwidth]{pics/ICE2_Erste_Klasse.pdf}\hspace{1mm}\includegraphics[width=.365\textwidth]{pics/schule.pdf}
	%\end{figure}
}


\setlength{\iskip}{.7em}
\frame{
	\myframetitle{Conclusion from the scenarios}
	
	\begin{itemize}
	\item Players don't move while playing\\[\iskip]
	\item Reliable supporting nodes move slowly\\[.1\iskip]
	\begin{itemize}
	  \item Use it only if it stays for a certain amount of time\\[1\iskip]
	\end{itemize}
	\item Other nodes may pass by at high speeds\\[.1\iskip]
	\begin{itemize}
	  \item Thus, they are only in range for a short amount of time\\[1\iskip]
	\end{itemize}
%	\item Clustering of players possible\\[.1\iskip]
%	\begin{itemize}
%	  \item Game Servers can be seen as cluster heads\\[1\iskip]
%	\end{itemize}
	\item Prioritization of game traffic recommended\\[.1\iskip]
	\begin{itemize}
	  \item Background traffic may impede fast-paced games\\[1\iskip]
	\end{itemize}
	\end{itemize}
}



\setlength{\iskip}{.4em}
\frame{
	\myframetitle{
		\begin{minipage}[t]{.69\textwidth}
			Scenario A: Train Station
		\end{minipage}
		\begin{minipage}[t]{.3\textwidth}
			\hspace{2mm}\includegraphics[width=\textwidth]{pics/DeutscheBahn_gobeirne.pdf}
		\end{minipage}
	}

	\vspace{-12ex}
	%\hspace{5mm}\includegraphics[width=.4\textwidth]{/home/wellnitz/doc/conferences/game-on-2006/pics/DeutscheBahn_gobeirne.pdf}
        	\begin{itemize}
	\item Medium sized area (e.g. $100\times250\,m^2$)\\[\iskip]
	\item User mobility\\[.2\iskip]
	\begin{itemize}
		\item Players wait on platforms (no mobility)\\[\iskip]
		\item Supporting nodes walk around ($v \approx 2\mps$)\\[\iskip]
		\item Trains may pass at speeds up to $ 25\mps$\\[\iskip]
	\end{itemize}
	\item Commercial WLAN infrastructure may be present\\[\iskip]
	\item Players usually stay no longer than 15~minutes\\[\iskip]
	\item Also generally true for other mass transportation systems\\[\iskip]
	\end{itemize}
}




\frame{
	\myframetitle{
		\begin{minipage}[t]{.64\textwidth}
			Scenario B: Train Ride
		\end{minipage}
		\begin{minipage}[t]{.35\textwidth}
			\hspace{2mm}\includegraphics[width=\textwidth]{pics/ICE2_Erste_Klasse.pdf}
		\end{minipage}
	}
	
	\vspace{-6em}
	
	\begin{itemize}
	\item Long and narrow area 
		\begin{itemize}
		\item E.g. $3\times175\,m^2$
		\end{itemize}
	\item Passengers usually sit on their seats
		\begin{itemize}
		\item Scenario is mainly static
		\end{itemize}
	\item People move at train stops 
		\begin{itemize}
		\item To get on and off the train
		\end{itemize}
	\item No alternative route during network congestion or disruption 
	\item Player usually stays longer than 10 minutes (up to several hours)
	\end{itemize}
}






%\frame{
%	\myframetitle{Scenario C: School Yard}
%	
%	\begin{itemize}
%	\item gaga
%	\end{itemize}
%}
%
%
%\frame{
%	\myframetitle{Scenario D: Mixed reality}
%	
%	\begin{itemize}
%	\item gaga
%	\end{itemize}
%}



\end{document}
