Automatic Table Extension with Open Data

With thousands of data sources available on the web as well as within organisations, data scientists increasingly spend more time searching for data than analysing it. To ease the task of find and integrating relevant data for data mining projects, this dissertation presents two new methods for automatic table extension. Automatic table extension systems take over the task of tata discovery and data integration by adding new columns with new information (new attributes) to any table. The data values in the new columns are extracted from a given corpus of tables

Moving elements in list CRDTs

Conflict-free Replicated Data Types (CRDTs) for lists allow multiple users to concurrently insert and delete elements in a shared list object. However, existing algorithms behave poorly when users concurrently move list elements to a new position (i.e. reorder the elements in the list). We demonstrate the need for such a move operation, and describe an algorithm that extends a list CRDT with an explicit move operation. Our algorithm can be used in conjunction with any existing list CRDT algorithm. In addition to moving a single list element, we also discuss the open problem of moving ranges of elements.Leverhulme Trust Early Career Fellowship Isaac Newton Trus

The Art of the Fugue: Minimizing Interleaving in Collaborative Text Editing

Most existing algorithms for replicated lists, which are widely used in collaborative text editors, suffer from a problem: when two users concurrently insert text at the same position in the document, the merged outcome may interleave the inserted text passages, resulting in corrupted and potentially unreadable text. The problem has gone unnoticed for decades, and it affects both CRDTs and Operational Transformation. This paper defines maximal non-interleaving, our new correctness property for replicated lists. We introduce two related CRDT algorithms, Fugue and FugueMax, and prove that FugueMax satisfies maximal non-interleaving. We also implement our algorithms and demonstrate that Fugue offers performance comparable to state-of-the-art CRDT libraries for text editing.Comment: 16 pages, 10 figure

Strengthening Public Key Authentication Against Key Theft (Short Paper)

Authentication protocols based on an asymmetric keypair provide strong authentication as long as the private key remains secret, but may fail catastrophically if the private key is lost or stolen. Even when encrypted with a password, stolen key material is susceptible to offline brute-force attacks. In this paper we demonstrate a method for rate-limiting password guesses on stolen key material, without requiring special hardware or changes to servers. By slowing down offline attacks and enabling easy key revocation our algorithm reduces the risk of key compromise, even if a low-entropy password is used

PushPin: Towards Production-Quality Peer-to-Peer Collaboration

Fully peer-to-peer application software promises many benefits over cloud software, in particular, being able to function indefinitely without requiring servers. Research on distributed consistency mechanisms such as CRDTs has laid the foundation for P2P data synchronisation and collaboration. In this paper we report on our experience in taking these technologies beyond research prototypes, and working towards commercial-grade P2P collaboration software. We identify approaches that work well in our experience, such as the functional reactive programming paradigm, and highlight areas in need of further research, such as the reliability of NAT traversal and usability challenges.Leverhulme Trust Early Career Fellowship Isaac Newton Trus