Tourism provides the foundation for user-generated content and online communities, allowing travellers to search for, receive and exchange information before or after trip. Virtual tourism environments, impersonating community members as avatars in a 3D world, provide a new way of communication and interaction possibilities. What is still missing is the support of the on-trip phase of the touri...

From user-generated content platforms to shopping portals, an important feature of websites is to identify which contents or items are the most popular and list them on the front page – assuming these contents are also the most interesting. In this paper, we investigate how social influence effect on popularity can violate this assumption, by studying data from a major news aggregator website w...

Social media comprises interactive applications and platforms for creating, sharing and exchange of user-generated contents. The past ten years have brought huge growth in social media, especially online social networking services, and it is changing our ways to organize and communicate. It aggregates opinions and feelings of diverse groups of people at low cost. Mining the attributes and conte...

UGC (User-generated content) websites routinely deploy incentive hierarchies, where users achieve increasingly higher status in the community after achieving increasingly more difficult goals, to motivate users to contribute. Yet the existing empirical literature remains largely unclear whether such hierarchies are indeed effective in inducing user contributions. We gathered data from a large o...

Despite the outstanding growth of social network sites in recent years, more research is needed to better understand how users' intentions to share their experiences with products and brands are formed through these applications. With this in mind, this study takes the Unified Theory of Acceptance and Use of Technology 2 (UTAUT2) as a reference and develops an extended model by considering the ...

Online reviews are a dominant resource for consumer decisions but what leads users to write reviews remains largely unexamined. Extant research on user content generation has primarily focused on what motivates users to contribute content, and less on the effects of informational and social environment surrounding these users. The aim of this study is to examine how a user’s contribution to an ...

In order to extract meaningful phrases from corpora (e. g. in an information retrieval context) intensive knowledge of the domain in question and the respective documents is generally needed. When moving to a new domain or language the underlying knowledge bases and models need to be adapted, which is often time-consuming and labor-intensive. This paper adresses the described challenge of phras...

The widespread popularity of the Web has supported collaborative efforts to build large collections of community-contributed media. For example, social video-sharing communities like YouTube are incorporating ever-increasing amounts of user-contributed media, or photo-sharing communities like Flickr are managing a huge photographic database at a large scale. The variegated abundance of multimod...

The fast growth of user-generated content puts a significant burden on the current network infrastructure. By implementing caching functionality on network infrastructure, we can effectively eliminate redundant traffic, reduce delay and achieve other goals. In my thesis, we utilize optimization model and design of heuristic to study and develop novel caching strategies with multiple objectives ...

Two short X-ray exposures (< 3600 s each) of the radio-quiet Seyfert 1.2 galaxy UGC 3973 (Mrk 79) were conducted with XMM-Newton as part of an AGN snap-shot survey. In this paper we concentrate on the significance and possible origin of a narrow 8 keV (rest frame) line-like emission feature detected with the pn instrument during the second observation. Simulations show that the feature is signi...