Hyoungshick Kim

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Many networks are dynamic in that their topology changes rapidly--on the same time scale as the communications of interest between network nodes. Examples are the human contact networks involved in the transmission of disease, ad hoc radio networks between moving vehicles, and the transactions between principals in a market. While we have good models of(More)
A number of web service firms have started to authenticate users via their social knowledge, such as whether they can identify friends from photos. We investigate attacks on such schemes. First, attackers often know a lot about their targets; most people seek to keep sensitive information private from others in their social circle. Against close enemies,(More)
We propose an effective pattern lock strength meter to help users choose stronger pattern locks on Android devices. To evaluate the effectiveness of the proposed meter with a real world dataset (i.e., with complete ecological validity), we created an Android application called EnCloud that allows users to encrypt their Dropbox files. 101 pattern locks(More)
Many research efforts for image encryption schemes have elaborated for designing nonlinear functions since security of these schemes closely depends on inherent characteristics of non-linear functions. It is commonly believed that a chaotic map can be used as a good candidate of a nonlinear component for image encryption schemes. We propose a new image(More)
Spam messages are an increasing threat to mobile communication. Several mitigation techniques have been proposed, including white and black listing, challenge-response and content-based filtering. However, none are perfect and it makes sense to use a combination rather than just one. We propose an anti-spam framework based on the hybrid of contentbased(More)
Real technological, social and biological networks evolve over time. Predicting their future topology has applications to epidemiology, targetedmarketing, network reliability and routing in ad hoc and peer-to-peer networks. The key problem for such applications is usually to identify thenodes thatwill be inmore important positions in the future. Previous(More)
Nowadays, the use of social media such as Twitter is necessary to monitor trends of people on political issues. As a case study, we collected the main stream of Twitter related to the 2010 UK general election during the associated period. We analyse the characteristics of the three main parties in the election. Also, we propose a simple and practical(More)
In modern politics, parties and individual candidates must have an online presence and usually have dedicated social media coordinators. In this context, we study the usefulness of analysing Twitter messages to identify both the characteristics of political parties and the political leaning of users. As a case study, we collected the main stream of Twitter(More)