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Publications (36)
Tokens have proliferated across blockchains in terms of number, market capitalisation and utility. Some tokens are tokenised versions of existing tokens -- known variously as wrapped tokens, fractional tokens, or shares. The repeated application of this process creates matryoshkian tokens of arbitrary depth. We perform an empirical analysis of toke...
The Bisq trade protocol is a key component of the Bisq decentralised exchange, allowing users to trade with one another in a decentralised manner. However, the protocol publishes trade data to the Bitcoin blockchain. In this paper, we analyse the privacy risks this creates for users. Specifically, we present two new heuristics, one to identify Bisq...
The Bisq Trade Protocol and the Bisq DAO are core components of Bisq, a decentralised cryptocurrency exchange. The Bisq Trade Protocol systematises the peer-to-peer trading of Bitcoin for other currencies and the Bisq DAO decentralises the governance and finance functions of the entire exchange. However, by following the Bisq Trade Protocol and int...
The Bisq DAO is a core component of Bisq, a decentralized cryptocurrency exchange. The purpose of the Bisq DAO is to decentralize the governance and finance functions of the exchange. However, by interacting with the Bisq DAO, participants necessarily publish data to the Bitcoin blockchain and broadcast additional data to the Bisq peer-to-peer netw...
Airdrops are a popular method of distributing cryptocurrencies and tokens. While often considered risk-free from the point of view of recipients, their impact on privacy is easily overlooked. We examine the Clam airdrop of 2014, a forerunner to many of today's airdrops, that distributed a new cryptocurrency to every address with a non-dust balance...
Address clustering tries to construct the one-to-many mapping from entities to addresses in the Bitcoin system. Simple heuristics based on the micro-structure of transactions have proved very effective in practice. In this paper we describe the primary reasons behind this effectiveness: address reuse, avoidable merging, super-clusters with high cen...
We assess the potential of network motif profiles to characterize ego-networks in much the same way that a bag-of-words strategy allows text documents to be compared in a vector space framework. This is potentially valuable as a generic strategy for comparing nodes in a network in terms of the network structure in which they are embedded. In this p...
The workshops day at the Sixth International Conference on Weblogs and Social Media included three full-day workshops (Social Media Visualization, Real-Time Analysis and Mining of Social Streams, and When the City Meets the Citizen) and one half day workshop (The Potential of Social Media Tools and Data for Journalists in the News Media). Workshops...
The workshops day at the Sixth International Conference on Web logs and Social Media included three full-day workshops (Real-Time Analysis and Mining of Social Streams, Social Media Visualization, and When the City Meets the Citizen) and one half-day workshop (The Potential of Social Media Tools and Data for Journalists in the News Media Industry)....
In network analysis the ability to characterize nodes based on their attributes and surrounding network structure is a fundamental problem. For example, in financial transaction networks, it allows us to identify typical and anomalous behaviour -- important for uncovering fraudulent behaviour. Egocentric network motif analysis is a counting algorit...
Because the production of Wikipedia articles is a collaborative process, the edit network around a article can tell us something about the quality of that article. Articles that have received little attention will have sparse networks; at the other end of the spectrum, articles that are Wikipedia battle grounds will have very crowded networks. In t...
EgoNav is a visual analytics system that characterizes egos based on the relationship structure of their egocentric networks and presents the results as a spatialization. An ego, or individual node in a network, is most closely related to its neighbors, and to a lesser degree, to its neighbor's neighbors. For example, in social networks, people are...
Like other social media websites, YouTube is not immune from the attention of
spammers. In particular, evidence can be found of attempts to attract users to
malicious third-party websites. As this type of spam is often associated with
orchestrated campaigns, it has a discernible network signature, based on
networks derived from comments posted by u...
As the popularity of content sharing websites such as YouTube and Flickr has
increased, they have become targets for spam, phishing and the distribution of
malware. On YouTube, the facility for users to post comments can be used by
spam campaigns to direct unsuspecting users to bogus e-commerce websites. In
this paper, we demonstrate how such campa...
Good Wikipedia articles are authoritative sources due to the collaboration of a number of knowledgeable contributors. This is the many eyes idea. The edit network associated with a Wikipedia article can tell us something about its quality or authoritativeness. In this paper we explore the hypothesis that the characteristics of this edit network are...
The identification of anomalous user behaviour is important in a number of application areas, since it may be indicative of fraudulent activity. In the work presented here, the focus is on the identification and subsequent investigation of suspicious interactions in a network of financial transactions. A network is constructed from data from a peer...
Anonymity in Bitcoin, a peer-to-peer electronic currency system, is a
complicated issue. Within the system, users are identified by public-keys only.
An attacker wishing to de-anonymize its users will attempt to construct the
one-to-many mapping between users and public-keys and associate information
external to the system with the users. Bitcoin t...
Wikipedia works because of the many eyes idea. Good Wikipedia pages are au-thoritative sources because a number of knowledgeable contributors have collab-orated to produce an authoritative article on a topic. In this paper we explore the hypothesis that the extent to which the many eyes idea is true for a specific article can be assessed by looking...
The k-level crossing minimization problem for graphs has received much interest in the graph drawing literature. In this paper
we focus on the special case of trees. We show that the 2-level crossing minimization problem for trees where the order of
the vertices on one level is fixed is solvable in quadratic time. We also show that the k-level cros...
Given a dataset comprising a temporal sequence of communications between actors, how can we visualize the `flow' of communication over time? Current practice transforms the dataset into a dynamic graph - vertices represent the actors and directed edges represent the communications. The directed edges are added and removed over time. There are then...
When developing an Adaptive Learning System (ALS), users are generally consulted (if at all) towards the end of the development cycle. This can limit users' feedback to the charac- teristics and idiosyncrasies of the system at hand. It can be dicult to extrapolate principles and requirements, common to all ALSs, that are rated highly by users. To a...
Current practice in adaptation modeling assumes that concepts and relationships between concepts are the fundamental building blocks of any adaptive course or adaptive application. This assumption underlies many of the mismatches we nd between the syntax of an adaptation model and the semantics of thèreal-world' entity it is trying to model, e.g. p...
This research report outlines a preliminary definition and design of a concept relationship type (CRT) tool. Objectives and requirements of a CRT tool for representing relationship types based on the domain model (DM) and for defining adaptation rules towards a conceptual adaptation model (CAM) are investigated. Functionalities and components const...
A directed graph can model any ordered relationship between objects. However, visualizing such graphs can be a challenging task. If the graph is undirected, a popular strategy is to choose a significant spanning tree, nominate a vertex as the root, for example the vertex whose distance from all other vertices is minimal, hang the significant spanni...
We describe a practical method to test a leveled graph for level planarity and provide a level planar layout of the graph if the test succeeds, all in quadratic running-time. Embedding constraints restricting the order of incident edges around the vertices are allowed.
A directed graph can model any ordered relationship between objects. However, visualizing such graphs can be a challenging task. If the graph is undirected, a popular strategy is to choose a significant spanning tree, nominate a vertex as the root, for example the vertex whose distance from all other vertices is minimal, hang the significant spanni...
We consider the problem of layering a directed acyclic graph with minimum dummy nodes. We present a new Integer Linear Programming (ILP) formulation of the problem based on a set of fundamental cycles in the underlying undirected graph and show that it can be solved in polynomial time. We outline some of the advantages of the formulation. Each solu...
The academic user base of an Adaptive Learning System (ALS) can be partitioned in two: the learners and the teachers (encompassing both content authors and tutors). Learners come from a diverse set of backgrounds with varying abilities and motivation and hence, have very individual learning requirements [2, 6, 7]. The time and eort they can devote...