Scientific Publications

This site contains a collection of scientific publications by Sebastian Straub.

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Master's Thesis (2017): Towards Collaborative Session-based Semantic Search

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In recent years, the most popular web search engines have excelled in their ability to answer short queries that require clear, localized and personalized answers. When it comes to complex exploratory search tasks however, the main challenge for the searcher remains the same as back in the 1990s: Trying to formulate a single query that contains all the right keywords to produce at least some relevant results.

In this work we want to investigate new ways to facilitate exploratory search by making use of context information from the user's entire search process. Therefore we present the concept of session-based semantic search, with an optional extension to collaborative search scenarios. To improve the relevance of search results we expand queries with terms from the user's recent query history in the same search context (session-based search). We introduce a novel method for query classification based on statistical topic models which allows us to track the most important topics in a search session so that we can suggest relevant documents that could not be found through keyword matching.

To demonstrate the potential of these concepts, we have built the prototype of a session-based semantic search engine which we release as free and open source software. In a qualitative user study that we have conducted, this prototype has shown promising results and was well-received by the participants.

Bachelor's Thesis (2012): Cartography in a Gameful Context

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Maps shape our view of the world and help us in our everyday lives to orient in unfamiliar territory. The art of creating maps however was reserved to a privileged group of people for a long time. Today's progresses in technology have opened it to anyone with internet access, as free crowdsourced projects have emerged, dedicated to create an open map of the world. However, editing the map and contributing data is still harder than necessary and so the existing projects did not yet hit the masses.

To solve this problem, cartography-related games are proposed in this thesis. Their goal is to unite cartographic work and gaming concepts in an easy to use abstraction layer, ready to be applied in a global, crowdsourced scale. The players should be enabled to participate immediately, without any cartographic background, and use their local knowledge to submit valuable geographic information. This approach makes it possible to create maps of unprecedented detail and actuality, which can make life easier and open whole new application ares for people with special interests (e.g. hiking, cycling) or disabilities (e.g. for blind people).

This thesis will give an overview of ludic ways to contribute geographic data and provide background information about the concerning topics cartography, humanbased computation and games in general. Based on that, abstract concepts for cartography-games have been developed and three exemplary game descriptions are provided. The goal of this thesis is to discover, if cartographic work is possible and feasible in a gameful context.

Talks

Term Papers

  • 2016-12-16. Straub S.: Foundations of Session-Based Collaborative Search (PDF)
  • 2016-06-12. Straub S.: Live-Hacking: Exploiting common security vulnerabilities for fun and profit (PDF)
  • 2015-07-14. Straub S.: GraphLab - a review of the distributed data analysis platform (PDF)
  • 2014-12-16. Straub S.: Anonymous Online Payment Systems (PDF)
  • 2012-03-14. Brunner H., Straub S.: Lazy Rebuilding (PDF)
  • 2011-08-18. Straub S.: Einfluss zivilgesellschaftlicher Foren auf die Internetpolitik in Deutschland (PDF)