The Wavelet Trie: Maintaining an Indexed Sequence of Strings in Compressed Space

An indexed sequence of strings is a data structure for storing a string sequence that supports random access, searching, range counting and analytics operations, both for exact matches and prefix search. String sequences lie at the core of column-oriented databases, log processing, and other storage and query tasks. In these applications each string can appear several times and the order of the strings in the sequence is relevant. The prefix structure of the strings is relevant as well: common prefixes are sought in strings to extract interesting features from the sequence. Moreover, space-efficiency is highly desirable as it translates directly into higher performance, since more data can fit in fast memory. We introduce and study the problem of compressed indexed sequence of strings, representing indexed sequences of strings in nearly-optimal compressed space, both in the static and dynamic settings, while preserving provably good performance for the supported operations. We present a new data structure for this problem, the Wavelet Trie, which combines the classical Patricia Trie with the Wavelet Tree, a succinct data structure for storing a compressed sequence. The resulting Wavelet Trie smoothly adapts to a sequence of strings that changes over time. It improves on the state-of-the-art compressed data structures by supporting a dynamic alphabet (i.e. the set of distinct strings) and prefix queries, both crucial requirements in the aforementioned applications, and on traditional indexes by reducing space occupancy to close to the entropy of the sequence

Between patronage and good governance: organizational arrangements in (local) public appointment processes

This article investigates whether certain organizational arrangements in (local) public appointment processes could encourage the use of appointments as a tool of good governance rather than as a tool of patronage. Specifically, we studied the role of six organizational arrangements in 10 case studies of intra- and inter-organizational public appointment processes held in Italian local government. We found that good governance (in terms of perception of overall integrity and fairness) was found in processes of public appointments where there was independent scrutiny, and when the process involved local councillors and/or external stakeholders – that is, actors beyond those with the formal power to appoint. In these cases, making appointments was seen as a tool of good governance rather than of patronage. These organizational arrangements were more relevant than other ones such as the transparency of public advertisements, job descriptions and educational/professional requirements, and media and public awareness. The article describes the relevant literature and the research study, and discusses implications for research, policy and management

The new public corruption: Old questions for new challenges

This paper focuses on corruption in public procurement. It describes the contemporary face of corruption by investigating the role of public accountability in the fight against corruption. The paper describes a specific episode of corruption relative to the awarding of government contracts for big events, such as the celebration of the 150th anniversary of Italian unification. Relying on the philosophical insights of Rousseau, Popper, Kant and others, the study suggests the need for enabling a democratic control and constructing a public ethics for the common good

New development: Accounting for human-made disasters—comparative analysis of the support to Ukraine in times of war

publishedVersio

The changing roles of internal auditors in the Ukrainian central government

publishedVersio

Reverse decoupling : Ukrainian case of healthcare financing system reform

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Emerald in International Journal of Public Sector Management on 10/04/2020.Available online: https://www.emerald.com/insight/content/doi/10.1108/IJPSM-10-2019-0262/full/pdf?title=reverse-decoupling-ukrainian-case-of-healthcare-financing-system-reformacceptedVersio

Participatory budgeting as a form of dialogic accounting in Russia : Actors’ institutional work and reflexivity trap

Author's accepted version (post-print).acceptedVersio

Performance budgeting as a “creative distraction” of accountability relations in one Russian municipality

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Emerald in Journal of Accounting in Emerging Economies on 07/05/2020.Available online: https://www.emerald.com/insight/content/doi/10.1108/JAEE-08-2019-0164/full/htmlacceptedVersio