ABSTRACT
While traditional knowledge services are mainly delivered by the experts with domain-specic knowledge, recent advances of information and communication technologies (e.g., smartphones and Web 2.0) have dramatically changed the nature of knowledge services. These technologies have facilitated ubiquitous sensing and networked collaboration among people, thus signicantly broadening the range of knowledge services and lowering the knowledge transfer barriers. People generate signicant amount of content and share it with other users via Web 2.0 services (e.g., YouTube and Twitter). Collaboration over the Internet is common as one can easily create an online project with tens of thousands of participants (called crowdsourcing), for example, Wikipedia, online Q&A services, and Innocentives. Further, sensing happens everywhere, ranging from surveillance cameras on the streets to smartphone sensors (e.g., collecting mobility traces of users) to even human sensors (e.g., sensing social events). This dramatic shift of ubiquitous sensing and collaboration has enabled new types of knowledge services called “ubiquitous knowledge services.” The key role of ubiquitous knowledge services is to seamlessly integrate content from various sources at large scales and to derive new values for end users in ways that the contributor of the content did not plan or imagine (Figure 18.1).
