Organizing conference sessions around themes improves the experience for attendees. However, the session creation process can be difficult and time-consuming due to the amount of expertise and effort required to consider alterna-tive paper groupings. We present a collaborative web appli-cation called Frenzy to draw on the efforts and knowledge of an entire program committee. Frenzy comprises (a) inter-faces to support large numbers of experts working collec-tively to create sessions, and (b) a two-stage process that decomposes the session-creation problem into meta-data elicitation and global constraint satisfaction. Meta-data elicitation involves a large group of experts working simul-taneously, while global constraint satisfaction involves a smaller group that uses the meta-data to form sessions. We evaluated Frenzy with 48 people during a deployment at the CSCW 2014 program committee meeting. The ses-sion making process was much faster than the traditional process, taking 88 minutes instead of a full day. We found that meta-data elicitation was useful for session creation. Moreover, the sessions created by Frenzy were the basis of the CSCW 2014 schedule. Author Keywords Crowdsourcing; groupware; communitysourcing

Organizing conference sessions around themes improves the experience for attendees. However, the session creation process can be difficult and time-consuming due to the amount of expertise and effort required to consider alterna-tive paper groupings. We present a collaborative web appli-cation called Frenzy to draw on the efforts and knowledge of an entire program committee. Frenzy comprises (a) inter-faces to support large numbers of experts working collec-tively to create sessions, and (b) a two-stage process that decomposes the session-creation problem into meta-data elicitation and global constraint satisfaction. Meta-data elicitation involves a large group of experts working simul-taneously, while global constraint satisfaction involves a smaller group that uses the meta-data to form sessions. We evaluated Frenzy with 48 people during a deployment at the CSCW 2014 program committee meeting. The ses-sion making process was much faster than the traditional process, taking 88 minutes instead of a full day. We found that meta-data elicitation was useful for session creation. Moreover, the sessions created by Frenzy were the basis of the CSCW 2014 schedule. Author Keywords Crowdsourcing; groupware; communitysourcing

Abstract. The areal modeling of the extremes of a natural process such as rainfall or temperature is important in environmental statistics; for example, understanding extreme areal rainfall is crucial in flood protection. This ar-ticle reviews recent progress in the statistical modeling of spatial extremes, starting with sketches of the necessary elements of extreme value statistics and geostatistics. The main types of statistical models thus far proposed, based on latent variables, on copulas and on spatial max-stable processes, are described and then are compared by application to a data set on rain-fall in Switzerland. Whereas latent variable modeling allows a better fit to marginal distributions, it fits the joint distributions of extremes poorly, so appropriately-chosen copula or max-stable models seem essential for suc-cessful spatial modeling of extremes.

ii iv vTo my parents vi vii Acknowledgements I would first and foremost extend my whole-hearted gratitude to my advisors, An-drea Arpaci-Dusseau and Remzi Arpaci-Dusseau. Andrea and Remzi are the reason that I had the opportunity for this exceptional Ph.D. journey. To this day, I still re-member the moment when they took me as their student and the joy and hope in my heart. Andrea and Remzi have showed me what systems research is like and how much fun and challenging it can be. Before this journey with them, I had always liked and believed in the beauty of mathematics and theory. My initial interest in systems research happened when I took Remzi’s Advanced Operating Systems

Hiermit versichere ich, die vorliegende Diplomarbeit selbstständig und unter ausschliesslicher Verwendung der angegebenen Quellen und Hilfsmittel angefertigt zu haben. Diese Arbeit hat in gleicher oder ähnlicher Form noch keiner Prüfungsbehörde vorgelegen. Darmstadt, 14. Februar 2006

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