VLDB 2026 Research / reviewers in the wild / expert
João Rulff
dblp:297/4627
· DBLP profile ↗
10ranked-venue papers
1as first author
10since 2021 · last 2026
0000-0003-3341-7059ORCID · verified
Domains — the database's venue-derived domains; a paper can count in several
Graphics, computer vision, multimedia, augmented reality and games · 6 · 1 first-author · 6 since 2021Human-computer interaction and ubiquitous computing · 4 · 4 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | InsightAR: A Tool for Multi-modal Summarization and Interactive Analysis of AR-based Egocentric Task Videos
Guande Wu, Dishita G. Turakhia, Eden Wu, Sonia Castelo Quispe, João Rulff, Erin McGowan, Jianben He, Cláudio T. Silva |
AVI | 5 |
| 2026 | UrbanClipAtlas: A Visual Analytics Framework for Event and Scene Retrieval in Urban VideosabstractAbstract Extracting actionable insights from long‐duration urban videos is often labor‐intensive: analysts must manually sift through raw footage to pinpoint target events or uncover broader behavioral trends. In this work, we present U rban C lip A tlas , a visual analytics system for exploring long urban videos recorded at street intersections. U rban C lip A tlas combines retrieval‐augmented generation (RAG), taxonomy‐aware entity extraction, and video grounding to support event retrieval and interpretation. The system segments extended recordings into short clips, generates textual descriptions with a vision–language model, and indexes them for semantic retrieval. A knowledge graph maps entities and relations from LLM answers onto a domain‐specific taxonomy and aligns them with detected objects and trajectories to support visual grounding and verification. U rban C lip A tlas supports scene retrieval through an augmented chat‐based interface and improves scene interpretation by tightly aligning textual outputs with video evidence. This design strengthens the connection between textual reasoning and visual evidence, reducing the effort required to validate model outputs and refine hypotheses. We demonstrate the usefulness of U rban C lip A tlas on the StreetAware dataset through two case studies involving hazardous scenarios and crossing dynamics at street intersections. U rban C lip A tlas helps analysts reason about safety‐ and mobility‐related patterns across large urban video collections. Joel Perca, Luis Sante, Juanpablo Heredia, João Rulff, Cláudio T. Silva, Jorge Poco |
Comput. Graph. Forum | 4 |
| 2025 | HuBar: A Visual Analytics Tool to Explore Human Behavior Based on fNIRS in AR Guidance SystemsabstractThe concept of an intelligent augmented reality (AR) assistant has significant, wide-ranging applications, with potential uses in medicine, military, and mechanics domains. Such an assistant must be able to perceive the environment and actions, reason about the environment state in relation to a given task, and seamlessly interact with the task performer. These interactions typically involve an AR headset equipped with sensors which capture video, audio, and haptic feedback. Previous works have sought to facilitate the development of intelligent AR assistants by visualizing these sensor data streams in conjunction with the assistant's perception and reasoning model outputs. However, existing visual analytics systems do not focus on user modeling or include biometric data, and are only capable of visualizing a single task session for a single performer at a time. Moreover, they typically assume a task involves linear progression from one step to the next. We propose a visual analytics system that allows users to compare performance during multiple task sessions, focusing on non-linear tasks where different step sequences can lead to success. In particular, we design visualizations for understanding user behavior through functional near-infrared spectroscopy (fNIRS) data as a proxy for perception, attention, and memory as well as corresponding motion data (acceleration, angular velocity, and gaze). We distill these insights into embedding representations that allow users to easily select groups of sessions with similar behaviors. We provide two case studies that demonstrate how to use these visualizations to gain insights about task performance using data collected during helicopter copilot training tasks. Finally, we evaluate our approach through an in-depth examination of a think-aloud experiment with five domain experts. Sonia Castelo Quispe, João Rulff, Parikshit Solunke, Erin McGowan, Guande Wu, Irán R. Román, Roque Lopez, Bea Steers, Qi Sun 0003, Juan Pablo Bello, Bradley Feest, Michael Middleton, Ryan McKendrick, Cláudio T. Silva |
IEEE Trans. Vis. Comput. Graph. | 2 |
| 2024 | PaleoScan: Low-Cost Easy-to-use High-Volume Fossil ScanningabstractFossils are crucial for understanding our natural history and the digitalization of fossils has paved the way for paleontologists to share and study them in greater detail. Yet, many fossil-dense regions, in particular low- and middle-income countries, lack the resources to digitalize their vast collections. This project reports on a collaboration between paleontologists and computer scientists to design, build, and operate a device that can be deployed in the field for digitizing a collection of thousands of fossils. We introduce PaleoScan, a user-friendly, cost-effective, high-volume scanner designed to expedite the digitization of extensive fossil collections. PaleoScan is a self-contained 3D scanning system consisting of a light and compact mirrorless camera, a microcontroller, a ChArUco calibration board, and user-controlled LEDs. Software and data processing is cloud-based, where the user interacts with the system through a web application. We deployed PaleoScan in a museum in Brazil with a world-class fossil collection. Our early results reveal its potential to revolutionize the scanning process for fossils. Cláudio T. Silva, Yurii Piadyk, João Rulff, Daniele Panozzo, Maria Beatriz Silva, Antonio Alamo Feitosa Saraiva, Naiara Cipriano Oliveira, Flaviana Jorge De Lima, Renan Alfredo Machado Bantim, Otavio Jose De Freitas Gomes, Akinobu Watanabe |
CHI | 3 |
| 2024 | ARTiST: Automated Text Simplification for Task Guidance in Augmented RealityabstractText presented in augmented reality provides in-situ, real-time information for users. However, this content can be challenging to apprehend quickly when engaging in cognitively demanding AR tasks, especially when it is presented on a head-mounted display. We propose ARTiST, an automatic text simplification system that uses a few-shot prompt and GPT-3 models to specifically optimize the text length and semantic content for augmented reality. Developed out of a formative study that included seven users and three experts, our system combines a customized error calibration model with a few-shot prompt to integrate the syntactic, lexical, elaborative, and content simplification techniques, and generate simplified AR text for head-worn displays. Results from a 16-user empirical study showed that ARTiST lightens the cognitive load and improves performance significantly over both unmodified text and text modified via traditional methods. Our work constitutes a step towards automating the optimization of batch text data for readability and performance in augmented reality. Guande Wu, Sonia Castelo Quispe, Shaoyu Chen, João Rulff, Cláudio T. Silva |
CHI | 5 |
| 2024 | : Visualization of AI-Assisted Task Guidance in ARabstractThe concept of augmented reality (AR) assistants has captured the human imagination for decades, becoming a staple of modern science fiction. To pursue this goal, it is necessary to develop artificial intelligence (AI)-based methods that simultaneously perceive the 3D environment, reason about physical tasks, and model the performer, all in real-time. Within this framework, a wide variety of sensors are needed to generate data across different modalities, such as audio, video, depth, speech, and time-of-flight. The required sensors are typically part of the AR headset, providing performer sensing and interaction through visual, audio, and haptic feedback. AI assistants not only record the performer as they perform activities, but also require machine learning (ML) models to understand and assist the performer as they interact with the physical world. Therefore, developing such assistants is a challenging task. We propose ARGUS, a visual analytics system to support the development of intelligent AR assistants. Our system was designed as part of a multi-year-long collaboration between visualization researchers and ML and AR experts. This co-design process has led to advances in the visualization of ML in AR. Our system allows for online visualization of object, action, and step detection as well as offline analysis of previously recorded AR sessions. It visualizes not only the multimodal sensor data streams but also the output of the ML models. This allows developers to gain insights into the performer activities as well as the ML models, helping them troubleshoot, improve, and fine-tune the components of the AR assistant. Sonia Castelo Quispe, João Rulff, Erin McGowan, Bea Steers, Guande Wu, Shaoyu Chen, Irán R. Román, Roque Lopez, Ethan Brewer, Chen Zhao 0013, Kyunghyun Cho, He He 0001, Qi Sun 0003, Huy T. Vo, Juan Pablo Bello, Michael Krone, Cláudio T. Silva |
IEEE Trans. Vis. Comput. Graph. | 2 |
| 2024 | Mountaineer: Topology-Driven Visual Analytics for Comparing Local ExplanationsabstractWith the increasing use of black-box Machine Learning (ML) techniques in critical applications, there is a growing demand for methods that can provide transparency and accountability for model predictions. As a result, a large number of local explainability methods for black-box models have been developed and popularized. However, machine learning explanations are still hard to evaluate and compare due to the high dimensionality, heterogeneous representations, varying scales, and stochastic nature of some of these methods. Topological Data Analysis (TDA) can be an effective method in this domain since it can be used to transform attributions into uniform graph representations, providing a common ground for comparison across different explanation methods. We present a novel topology-driven visual analytics tool, Mountaineer, that allows ML practitioners to interactively analyze and compare these representations by linking the topological graphs back to the original data distribution, model predictions, and feature attributions. Mountaineer facilitates rapid and iterative exploration of ML explanations, enabling experts to gain deeper insights into the explanation techniques, understand the underlying data distributions, and thus reach well-founded conclusions about model behavior. Furthermore, we demonstrate the utility of Mountaineer through two case studies using real-world data. In the first, we show how Mountaineer enabled us to compare black-box ML explanations and discern regions of and causes of disagreements between different explanations. In the second, we demonstrate how the tool can be used to compare and understand ML models themselves. Finally, we conducted interviews with three industry experts to help us evaluate our work. Parikshit Solunke, Vitória Guardieiro, João Rulff, Peter Xenopoulos, Gromit Yeuk-Yin Chan, Brian Barr, Luis Gustavo Nonato, Cláudio T. Silva |
IEEE Trans. Vis. Comput. Graph. | 3 |
| 2023 | Calibrate: Interactive Analysis of Probabilistic Model OutputabstractAnalyzing classification model performance is a crucial task for machine learning practitioners. While practitioners often use count-based metrics derived from confusion matrices, like accuracy, many applications, such as weather prediction, sports betting, or patient risk prediction, rely on a classifier's predicted probabilities rather than predicted labels. In these instances, practitioners are concerned with producing a calibrated model, that is, one which outputs probabilities that reflect those of the true distribution. Model calibration is often analyzed visually, through static reliability diagrams, however, the traditional calibration visualization may suffer from a variety of drawbacks due to the strong aggregations it necessitates. Furthermore, count-based approaches are unable to sufficiently analyze model calibration. We present Calibrate, an interactive reliability diagram that addresses the aforementioned issues. Calibrate constructs a reliability diagram that is resistant to drawbacks in traditional approaches, and allows for interactive subgroup analysis and instance-level inspection. We demonstrate the utility of Calibrate through use cases on both real-world and synthetic data. We further validate Calibrate by presenting the results of a think-aloud experiment with data scientists who routinely analyze model calibration. Peter Xenopoulos, João Rulff, Luis Gustavo Nonato, Brian Barr, Cláudio T. Silva |
IEEE Trans. Vis. Comput. Graph. | 2 |
| 2022 | Urban Rhapsody: Large-scale exploration of urban soundscapesabstractAbstract Noise is one of the primary quality‐of‐life issues in urban environments. In addition to annoyance, noise negatively impacts public health and educational performance. While low‐cost sensors can be deployed to monitor ambient noise levels at high temporal resolutions, the amount of data they produce and the complexity of these data pose significant analytical challenges. One way to address these challenges is through machine listening techniques, which are used to extract features in attempts to classify the source of noise and understand temporal patterns of a city's noise situation. However, the overwhelming number of noise sources in the urban environment and the scarcity of labeled data makes it nearly impossible to create classification models with large enough vocabularies that capture the true dynamism of urban soundscapes. In this paper, we first identify a set of requirements in the yet unexplored domain of urban soundscape exploration. To satisfy the requirements and tackle the identified challenges, we propose Urban Rhapsody, a framework that combines state‐of‐the‐art audio representation, machine learning and visual analytics to allow users to interactively create classification models, understand noise patterns of a city, and quickly retrieve and label audio excerpts in order to create a large high‐precision annotated database of urban sound recordings. We demonstrate the tool's utility through case studies performed by domain experts using data generated over the five‐year deployment of a one‐of‐a‐kind sensor network in New York City. João Rulff, Fabio Miranda 0001, Marcos Lage, Mark Cartwright, Graham Dove, Juan Pablo Bello, Cláudio T. Silva |
Comput. Graph. Forum | 1 |
| 2022 | ggViz: Accelerating Large-Scale Esports Game AnalysisabstractWhile esports organizations are increasingly adopting practices of conventional sports teams, such as dedicated analysts and data-driven decision-making, video-based game review is still the primary mode of game analysis. In conventional sports, advances in data collection have introduced systems that allow for sketch-based querying of game situations. However, due to data limitations, as well as differences in the sport itself, esports has seen a dearth of such systems. In this paper, we leverage player tracking data for Counter-Strike: Global Offensive (CSGO) to develop ggViz, a visual analytics system that allows users to query a large esports data set through game state sketches to find similar game states. Users are guided to game states of interest using win probability charts and round icons, and can summarize collections of states through heatmaps. We motivate our design through interviews with esports experts to especially address the issue of game review. We demonstrate ggViz's utility through detailed case studies and expert interviews with coaches, managers, and analysts from professional esports teams. Peter Xenopoulos, João Rulff, Cláudio T. Silva |
Proc. ACM Hum. Comput. Interact. | 2 |