EDBT 2026 Demo / reviewers in the wild / expert
Helen Oliver 0001
dblp:98/3200-1
· DBLP profile ↗
6ranked-venue papers
2as first author
4since 2021 · last 2026
0000-0003-1467-8165ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Databases, data management, data science and information retrieval · 4 · 4 since 2021Software engineering, systems software and programming languages · 2 · 1 first-author · 1 since 2021Artificial intelligence and machine learning · 1 · 1 since 2021Applied, interdisciplinary, general and emerging computing · 1 · 1 first-author
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | Rethinking Information Retrieval in a Re-Decentralised Web: Exploring the Feasibility and Quality of Search Across Personal Online DatastoresabstractTraditional information retrieval (IR) models, such as keyword-based and vector-based techniques, have long been used in centralized systems. However, the Web’s re-decentralization, with its focus on data ownership and privacy, calls for a re-evaluation of these methods in these settings. While standards for decentralized search enhance privacy to some extent, they also introduce computational overhead, black-box decision-making, and infrastructure complexity. Despite these challenges, traditional IR techniques remain largely unexplored in such environments. This article presents an innovative application of traditional IR models in the decentralized Web by adapting them for Personal Online Data Stores (PODs), where search parties have varying access rights. We explore their role in source selection, document ranking, and result merging, extending them to meet decentralized search demands. Using Solid PODs and a synthetic medical dataset, we evaluate these models in a privacy-sensitive environment. Our findings demonstrate that extended IR methods provide an effective balance of performance, interpretability, and efficiency. These approaches hold strong potential as privacy-preserving alternatives for decentralized search on a re-decentralized Web. Notably, our top-performing model achieved competitive results in top-item retrieval compared to centralized search systems, maintaining high relevance scores under both limited and full data access conditions. Mohammad Bahrani, Mohamed Ragab 0001, Helen Oliver 0001, Thanassis Tiropanis, Adriane Chapman, Alexandra Poulovassilis, George Roussos |
ACM Trans. Web | 3 |
| 2025 | ESPRESSO: Privacy-Preserving Keyword Search on Decentralized Data with Differential Visibility Constraints
Mohamed Ragab 0001, Mohamed Bahrani, Helen Oliver 0001, Thanassis Tiropanis, Alexandra Poulovassilis, Adriane Chapman, George Roussos |
CIKM | 3 |
| 2024 | Decentralized Search over Personal Online Datastores: Architecture and Performance EvaluationabstractData privacy and sovereignty are open challenges in today’s Web, which the Solid ( https://solidproject.org ) ecosystem aims to meet by providing personal online datastores (pods) where individuals can control access to their data. Solid allows developers to deploy applications with access to data stored in pods, subject to users’ permission. For the decentralised Web to succeed, the problem of search over pods with varying access permissions must be solved. The ESPRESSO framework takes the first step in exploring such a search architecture, enabling large-scale keyword search across Solid pods with varying access rights. This paper provides a comprehensive experimental evaluation of the performance and scalability of decentralised keyword search across pods on the current ESPRESSO prototype. The experiments specifically investigate how controllable experimental parameters influence search performance across a range of decentralised settings. This includes examining the impact of different text dataset sizes (0.5 MB to 50 MB per pod, divided into 1 to 10,000 files), different access control levels (10%, 25%, 50%, or 100% file access), and a range of configurations for Solid servers and pods (from 1 to 100 pods across 1 to 50 servers). The experimental results confirm the feasibility of deploying a decentralised search system to conduct keyword search at scale in a decentralised environment. Mohamed Ragab 0001, Yury Savateev, Helen Oliver 0001, Thanassis Tiropanis, Alexandra Poulovassilis, Adriane Chapman, Ruben Taelman, George Roussos |
ICWE | 3 |
| 2024 | ESPRESSO: A Framework to Empower Search on the Decentralized WebabstractAbstract The increasing centralization of the Web raises serious concerns regarding privacy, security, and user autonomy. In response, there has been a renewed interest in the development of secure personal information management systems and a movement towards decentralization. Decentralized personal online data stores (pods) represent a revolutionary example within this movement, built on the W3C’s existing guidelines – an approach exemplified by initiatives such as ( https://solidproject.org ). In the Solid paradigm, individuals store their personal data in pods and have absolute discretion when choosing to grant access to different users and applications. A barrier to the adoption of the pod approach is the predominant reliance on centralized indexes for search functionality in current Web and Web-based systems. This paper introduces the framework, which is designed to facilitate this new paradigm of large-scale searches within personal data stores while respecting the individual pod owners’ data access governance. The current ESPRESSO prototype integrates access control within pod indexes to enhance distributed keyword-based search. ESPRESSO’s unique contribution not only enhances search capabilities on the decentralized Web but also paves the way for future explorations in decentralized search technologies. Mohamed Ragab 0001, Yury Savateev, Helen Oliver 0001, Thanassis Tiropanis, Alexandra Poulovassilis, Adriane Chapman, George Roussos |
Data Sci. Eng. | 3 |
| 2016 | A design proto-pattern for continuously evaluated forecasting in IBM® InfoSphere® StreamsabstractSummary Design patterns relieve much of the difficulty of developing software solutions. As sources and volumes of generated data have increased in recent times, stream computing has emerged as a new paradigm for acquiring and harnessing the data's rich potential to provide insight in near real time. One prominent platform for processing streaming data is IBM® InfoSphere® Streams, but design patterns for the platform are relatively scarce. This article proposes a prototypical application design pattern for continuously evaluated forecasting on the IBM InfoSphere Streams platform. Towards demonstrating the prototypical pattern, the application was implemented in three real‐world scenarios: wind power, sentiment analysis, and stock market data. The purpose of this article is to specify the design proto‐pattern and describe its variants in each different implementation. We believe that the proto‐pattern will be applicable in IBM InfoSphere Streams to any data stream where forecasts over multiple forecast horizons are required. Copyright © 2015 John Wiley & Sons, Ltd. Helen Oliver 0001, Patrick E. McSharry |
Softw. Pract. Exp. | 1 |
| 2009 | A user-centred evaluation framework for the Sealife semantic web browsersabstractBACKGROUND: Semantically-enriched browsing has enhanced the browsing experience by providing contextualized dynamically generated Web content, and quicker access to searched-for information. However, adoption of Semantic Web technologies is limited and user perception from the non-IT domain sceptical. Furthermore, little attention has been given to evaluating semantic browsers with real users to demonstrate the enhancements and obtain valuable feedback. The Sealife project investigates semantic browsing and its application to the life science domain. Sealife's main objective is to develop the notion of context-based information integration by extending three existing Semantic Web browsers (SWBs) to link the existing Web to the eScience infrastructure. METHODS: This paper describes a user-centred evaluation framework that was developed to evaluate the Sealife SWBs that elicited feedback on users' perceptions on ease of use and information findability. Three sources of data: i) web server logs; ii) user questionnaires; and iii) semi-structured interviews were analysed and comparisons made between each browser and a control system. RESULTS: It was found that the evaluation framework used successfully elicited users' perceptions of the three distinct SWBs. The results indicate that the browser with the most mature and polished interface was rated higher for usability, and semantic links were used by the users of all three browsers. CONCLUSION: Confirmation or contradiction of our original hypotheses with relation to SWBs is detailed along with observations of implementation issues. Helen Oliver 0001, Gayo Diallo, Ed de Quincey, Dimitra Alexopoulou, Bianca Habermann, Patty Kostkova, Michael Schroeder 0001, Simon Jupp, Khaled Khelif, Robert Stevens 0001, Gawesh Jawaheer, Gemma Madle |
BMC Bioinform. | 1 |