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Pedro Oliveira

Publications and source records attributed to Pedro Oliveira.

10 recordsLinked to original sources

Governance in Practice: How Open Source Projects Define and Document Roles

Open source software (OSS) sustainability depends not only on code contributions but also on governance structures that define who decides, who acts, and how responsibility is distributed. We lack systematic empirical evidence of how projects formally codify roles and authority in written artifacts. This paper investigates how OSS projects define and structure governance through their GOVERNANCE.md files and related documents. We analyze governance as an institutional infrastructure, a set of explicit rules that shape participation, decision rights, and community memory. We used Institutional Grammar to extract and formalize role definitions from repositories hosted on GitHub. We decompose each role into scope, privileges, obligations, and life-cycle rules to compare role structures across communities. Our results show that although OSS projects use a stable set of titles, identical titles carry different responsibilities, and different labels describe similar functions, which we call role drift. Still, we observed that a few actors sometimes accumulate technical, managerial, and community duties. %This creates the Maintainer Paradox: those who enable broad participation simultaneously become governance bottlenecks. By understanding authority and responsibilities in OSS, our findings inform researchers and practitioners on the importance of designing clearer roles, distributing work, and reducing leadership overload to support healthier and more sustainable communities.

cs.SE

Governance Matters: Lessons from Restructuring the data.table OSS Project

Open source software (OSS) forms the backbone of industrial data workflows and enterprise systems. However, many OSS projects face operational risks due to informal or centralized governance. This paper presents a practical case study of data.table, a high-performance R package widely adopted in production analytics pipelines, which underwent a community-led governance reform to address scalability and sustainability concerns. Before the reform, data.table faced a growing backlog of unresolved issues and open pull requests, unclear contributor pathways, and bottlenecks caused by reliance on a single core maintainer. In response, the community initiated a redesign of its governance structure. In this paper, we evaluated the impact of this transition through a mixed-methods approach, combining a contributor survey (n=17) with mining project repository data. Our results show that following the reform, the project experienced a 200% increase in new contributor recruitment, a drop in pull request resolution time from over 700 days to under a week, and a 3x increase in contributor retention. Community sentiment improved around transparency, onboarding, and project momentum, though concerns around fairness and conflict resolution remain. This case study provides practical guidance for maintainers, companies, and foundations seeking to enhance OSS governance.

cs.SE

Emotion4MIDI: a Lyrics-based Emotion-Labeled Symbolic Music Dataset

We present a new large-scale emotion-labeled symbolic music dataset consisting of 12k MIDI songs. To create this dataset, we first trained emotion classification models on the GoEmotions dataset, achieving state-of-the-art results with a model half the size of the baseline. We then applied these models to lyrics from two large-scale MIDI datasets. Our dataset covers a wide range of fine-grained emotions, providing a valuable resource to explore the connection between music and emotions and, especially, to develop models that can generate music based on specific emotions. Our code for inference, trained models, and datasets are available online.

eess.AS

HPIM-DM: a fast and reliable dense-mode multicast routing protocol (extended version)

This paper proposes the HPIM-DM (Hard-state Protocol Independent Multicast - Dense Mode) multicast routing protocol. HPIM-DM is a hard-state version of PIM-DM that keeps its main characteristics but has faster convergence and better resilience to replay attacks. Like PIM-DM, HPIM-DM is meant for dense networks and supports its operation on a unicast routing protocol and reverse path forwarding checks. However, routers maintain sense of the multicast trees at all times, allowing fast reconfiguration in the presence of network failures or unicast route changes. This is achieved by (i) keeping information on all upstream neighbors from which multicast data can be received, (ii) ensuring the reliable transmission and sequencing of control messages, and (iii) synchronizing the routing information immediately when a new router joins the network. The protocol was fully implemented in Python, and the implementation is publicly available. Finally, the correctness of the protocol was extensively validated using model checking, logical reasoning and tests performed over the protocol implementation.

cs.NI

Issue Auto-Assignment in Software Projects with Machine Learning Techniques

Usually, managers or technical leaders in software projects assign issues manually. This task may become more complex as more detailed is the issue description. This complexity can also make the process more prone to errors (misassignments) and time-consuming. In the literature, many studies aim to address this problem by using machine learning strategies. Although there is no specific solution that works for all companies, experience reports are useful to guide the choices in industrial auto-assignment projects. This paper presents an industrial initiative conducted in a global electronics company that aims to minimize the time spent and the errors that can arise in the issue assignment process. As main contributions, we present a literature review, an industrial report comparing different algorithms, and lessons learned during the project.

cs.SE

Decay of solutions of the wave equation in expanding cosmological spacetimes

We study the decay of solutions of the wave equation in some expanding cosmological spacetimes, namely flat Friedmann-Lemaître-Robertson-Walker (FLRW) models and the cosmological region of the Reissner-Nordström-de Sitter (RNdS) solution. By introducing a partial energy and using an iteration scheme, we find that, for initial data with finite higher order energies, the decay rate of the time derivative is faster than previously existing estimates. For models undergoing accelerated expansion, our decay rate appears to be (almost) sharp.

gr-qc

Cosmic no-hair in spherically symmetric black hole spacetimes

We analyze in detail the geometry and dynamics of the cosmological region arising in spherically symmetric black hole solutions of the Einstein-Maxwell-scalar field system with a positive cosmological constant. More precisely, we solve, for such a system, a characteristic initial value problem with data emulating a dynamic cosmological horizon. Our assumptions are fairly weak, in that we only assume that the data approaches that of a subextremal Reissner-Nordström-de Sitter black hole, without imposing any rate of decay. We then show that the radius (of symmetry) blows up along any null ray parallel to the cosmological horizon ("near" $i^+$), in such a way that $r=+\infty$ is, in an appropriate sense, a spacelike hypersurface. We also prove a version of the Cosmic No-Hair Conjecture by showing that in the past of any causal curve reaching infinity both the metric and the Riemann curvature tensor asymptote those of a de Sitter spacetime. Finally, we discuss conditions under which all the previous results can be globalized.

gr-qc

Frequency-resolved optical gating of highly chirped ultrabroadband pulses

This article describes a simplified reconstruction algorithm for frequency resolved optical gating (FROG) measurements of highly (monotonically) chirped pulses. The FROG traces are calculated using the stationary phase approximation, significantly reducing the data size and convergence time compared to discrete Fourier transform based methods. The method is verified via second harmonic generation FROG simulations and measurements of pulses centred at 800nm with a bandwidth of 55nm stretched to 32ps at the 1% intensity level, corresponding to a time-bandwidth product of 830.

physics.ins-det

Interferometric method for the complete characterization of highly chirped ultrabroadband pulses

This article describes an interferometric method, called "Chirped Heterodyne Interferometry for Measuring Pulses" (CHIMP), for the complete characterization of highly (monotonically) chirped ultrabroadband optical pulses. CHIMP provides the spectrally dependent group delay dispersion (GDD) of the a chirped test pulse (CTP) via a simple direct algorithm and is verified via second harmonic generation (SHG) simulations and experimental measurements of pulses centred at 800nm with a bandwidth of 55nm stretched to 32ps at the 1% intensity level, corresponding to a time-bandwidth product of 830.

physics.optics

Managing your Private and Public Data: Bringing down Inference Attacks against your Privacy

We propose a practical methodology to protect a user's private data, when he wishes to publicly release data that is correlated with his private data, in the hope of getting some utility. Our approach relies on a general statistical inference framework that captures the privacy threat under inference attacks, given utility constraints. Under this framework, data is distorted before it is released, according to a privacy-preserving probabilistic mapping. This mapping is obtained by solving a convex optimization problem, which minimizes information leakage under a distortion constraint. We address practical challenges encountered when applying this theoretical framework to real world data. On one hand, the design of optimal privacy-preserving mechanisms requires knowledge of the prior distribution linking private data and data to be released, which is often unavailable in practice. On the other hand, the optimization may become untractable and face scalability issues when data assumes values in large size alphabets, or is high dimensional. Our work makes three major contributions. First, we provide bounds on the impact on the privacy-utility tradeoff of a mismatched prior. Second, we show how to reduce the optimization size by introducing a quantization step, and how to generate privacy mappings under quantization. Third, we evaluate our method on three datasets, including a new dataset that we collected, showing correlations between political convictions and TV viewing habits. We demonstrate that good privacy properties can be achieved with limited distortion so as not to undermine the original purpose of the publicly released data, e.g. recommendations.

cs.CR