Despite the services of sophisticated search engines like Google, there are a number of interesting information sources which are useful but largely inaccessible to current Web users. These information sources are often ad-hoc, location-specific and only useful for users over short periods of time, or relate to tacit knowledge of users or implicit knowledge in crowds. The solution presented in this paper addresses these problems by introducing an integrated concept of "location" and "presence" across the physical and virtual worlds enabling ad-hoc socializing of users interested in, or looking for similar information. While the definition of presence in the physical world is straightforward - through a spatial location and vicinity at a certain point in time - their definitions in the virtual world are neither obvious nor trivial. Based on a detailed analysis we provide an integrated spatial model spanning both worlds which enables us to define presence of users in a unified way. This integrated model allows us to enable ad-hoc socializing of users browsing the Web with users in the physical world specific to their joint information needs and allows us to unlock the untapped information sources mentioned above. We describe a proof-of-concept implementation of our model and provide an empirical analysis based on real-world experiments.
Browsing and searching the Web is still primarily an isolated task. @cite_5 conducted a survey showing that collaborative browsing is crucial for many users, but currently requires users to revert to out-of-band channels such as phone, e-mail or instant messaging. @cite_4 and @cite_26 are systems providing mechanisms for co-located collaboration, i.e., where several users gather around one computer. @cite_6 and @cite_10 extend this idea to collaborative browsing between users working with their own computers. (llaborative rowsing and earching) @cite_0 proposes a browser extension providing a proof-of-concept implementation that allows users visiting the same site to communicate with each other.
@cite_26 @cite_4 @cite_6 @cite_0 @cite_5 @cite_10
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Web search is often viewed as a solitary task; however, there are many situations in which groups of people gather around a single computer to jointly search for information online. We present the findings of interviews with teachers, librarians, and developing world researchers that provide details about users' collaborative search habits in shared-computer settings, revealing several limitations of this practice. We then introduce CoSearch, a system we developed to improve the experience of co-located collaborative Web search by leveraging readily available devices such as mobile phones and extra mice. Finally, we present an evaluation comparing CoSearch to status quo collaboration approaches, and show that CoSearch enabled distributed control and division of labor, thus reducing the frustrations associated with shared-computer searches, while still preserving the positive aspects of communication and collaboration associated with joint computer use. Today's Web browsers provide limited support for rich information-seeking and information-sharing scenarios. A survey we conducted of 204 knowledge workers at a large technology company has revealed that a large proportion of users engage in searches that include collaborative activities. We present the results of the survey, and then review the implications of these findings for designing new Web search interfaces that provide tools for sharing. Interactive tables can enhance small group colocated collaborative work in many domains. One application enabled by this new technology is copresent, collaborative search for digital content. For example, a group of students could sit around an interactive table and search for digital images to use in a report. We have developed TeamSearch, an application that enables this type of activity by supporting group specification of Boolean style queries. We explore whether TeamSearch should consider all group members' activities as contributing to a single query or should interpret them as separate, parallel search requests. The results reveal that both strategies are similarly efficient, but that collective query formation has advantages in terms of enhancing group collaboration and awareness, allowing users to bootstrap query specification skills, and personal preference. This suggests that team centric ills may offer benefits beyond the "staples" of efficiency and result quality that are usually considered when designing search interfaces. With the advent of networks that span administrative domains, increasing mobility, and even global-area networks, we find ourselves more and more often in situations where we do not know the potential parties accessing our system. Yet, we choose to collaborate with them: For example, we frequently browse unknown Web sites, or invite unknown parties to access our servers. I call a scenario in which parties choose to collaborate that do not necessarily trust each other, or even know each other, an ad-hoc collaboration . This dissertation investigates how we can protect our sensitive resources in the presence of ad-hoc collaboration. In particular, I study three ad-hoc collaboration scenarios and propose novel access control schemes for each of them. In my first system I propose and implement an access control mechanism for distributed Java applications that can span administrative domains. It uses an access control logic to allow servers to reason about the access privileges of unknown clients. My second system presents a simple security model for the personal computer, in which the user's workstation is divided into multiple desktops. Each desktop is sealed off from the others, confining the possibly dangerous results of ad-hoc collaboration. My last system investigates ad-hoc collaboration with hand-held computers. I present a framework that allows developers to write “split applications”: Part of the application runs on a trusted, but computationally limited, small computer, and part of the application runs on an untrusted, but more powerful PC.