HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

1 Despite the rapid proliferation of open data platforms, the accessibility and ease of use of data portals is low. This factor prevents citizens and civil society organizations from exploiting open data for their goals. The poor usability of current generation of open data platforms could be attributed to the fact that these platforms were not designed for non-technical users. They are typically software products developed "by programmers for programmers or technical users". Consequently, while reports about innovative use of open data by software developers and start-ups are common, there are very few reports about successful public use of open data to tackle concrete societal challenges. This paper provides the results and lessons learnt from the usability evaluation of the second alpha release of a next generation open data platform designed explicitly to support non-technical users. A scenario involving a transportation challenge in Dublin City was employed as the context for the evaluation of the platform. Findings provide some empirical basis for identifying important user interface design considerations, patterns for highly usable open data platforms and considerations for open data policy.

The increasing volumes of datasets published on open data platforms have had little impact on the public use of open data and perceived transparency of respective governments. At the same time, the innovation potentials of these datasets are far from realized due to many factors including poor quality of datasets. While past studies have attempted to catalog barriers to open data exploitation and use; few studies have focused on the role of the available open data platforms in tackling this problem. In addressing this gap, this research work examines the problems (or pathologies) associated with the use of current generation of open data platforms and perspectives of stakeholders on desirable features and affordances. Results from our analysis of existing platforms and stakeholders' views show several limiting factors on available platforms. Findings also provide insights into three categories of platform affordances that could spur greater use of open data published on these platforms and enhanced transparency of respective governments.

Open data platforms are central to the management and exploitation of data ecosystems. While existing platforms provide basic search capabilities and features for filtering search results, none of the existing platforms provide recommendations on related datasets. Knowledge of dataset relatedness is critical for determining datasets that can be mashed-up or integrated for the purpose of analysis and creation of data-driven services. When considering data platforms, such as data.gov with over 193,000 datasets or data.gv.uk with over 40,000 datasets, specifying dataset relatedness relationship manually is infeasible. In this paper, we approach the problem of discovering relatedness in datasets by employing the Kohonen Self Organsing Map (SOM) algorithm to analyze the metadata extracted from the Data Catalogue maintained on a platform. Our results show that this approach is very effective in discovering relatedness relationships among datasets. Findings also reveal that our approach could uncover interesting and valuable connections among domains of the datasets which could be further exploited for designing smarter data-driven services. Keywords-Semantic relatedness of datasets; data recommendation; open data platforms; e-government I. INTRODUCTION Open data platforms are central to data ecosystems. These data infrastructures mediate public access to the increasingly available open government and public data. In addition to providing access to available data, open data platforms enable organizations to manage their data catalogues, publish, explore, analyse and share their datasets. Currently, there are over ten known open data platforms including CKAN,