Publications de Daniel Gatica-Perez

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To go beyond the query-by-example paradigm in image retrieval, there is a need for semantic indexing of large image collections for intuitive text-based image search. Different models have been proposed to learn the dependencies between the visual content ...

Particle filtering (PF) is now established as one of the most popular methods for visual tracking. Within this framework, two assumptions are generally made. The first is that the data are temporally independent given the sequence of object states, and the ...

Background: Many addictive behaviours are influenced by the context in which they occur, but methods for simultaneously capturing the characteristics of a behaviour and its context are scarce. This study describes a smartphone application developed to docu ...

In this paper we present a multimodal analysis of emergent leadership in small groups using audio-visual features and discuss our experience in designing and collecting a data corpus for this purpose. The ELEA Audio-Visual Synchronized corpus (ELEA AVS) wa ...

This paper presents an original approach for shape-based analysis of ancient Maya hieroglyphs based on an interdisciplinary collaboration between computer vision and archaeology. Our work is guided by realistic needs of archaeologists and scholars who crit ...

Alcohol consumption is the number one risk factor for morbidity and mortality among young people. In late adolescence and early adulthood, excessive drinking and intoxication are more common than in any other life period, increasing the risk of adverse phy ...

A substantial body of research in multimodal interaction has studied how people naturally interact -face-to-face and through machinesand developed technology to analyze, support, and extend such forms of interaction. The talk will share personal experience ...

Human Activity Recognition (HAR) enables context-aware user experiences where mobile apps can alter content and interactions depending on user activities. Hence, smartphones have become valuable for HAR as they allow large, and diversified data collection. ...

While the task of automatically detecting eating events has been examined in prior work using various wearable devices, the use of smartphones as standalone devices to infer eating events remains an open issue. This paper proposes a framework that infers e ...

Rapport has been recognized as an important aspect of relationship building. While rapport in the context of human-human interaction has been widely studied, how it can be established and maintained in human-agent interaction has been studied only recently ...

Social media have transformed the Web into an interactive sharing platform where users upload data and media, comment on, and share this content within their social circles. Each content item is associated with an abundance of metadata and related informat ...

Graph Neural Networks (GNNs) have become a popular tool for learning on graphs, but their widespread use raises privacy concerns as graph data can contain personal or sensitive information. Differentially private GNN models have been recently proposed to p ...

With the increase in cheap commercially available sensors, recording meetings is becoming an increasingly practical option. With this trend comes the need to summarize the recorded data in semantically meaningful ways. Here, we investigate the task of auto ...

In this article, we define and address the problem of finding the visual focus of attention for a varying number of wandering people (VFOA-W) -- determining where a person is looking when their movement is unconstrained. VFOA-W estimation is a new and impo ...

Machine learning models trained with passive sensor data from mobile devices can be used to perform various inferences pertaining to activity recognition, context awareness, and health and well-being. Prior work has improved inference performance through t ...

We developed the Geographical Proportional-to-size Street-Intercept Sampling (GPSIS) method in order to obtain a sample of nightlife-goers which accounted for the diversity of spaces, patrons and locations within two Swiss cities. Popular nightlife zones w ...

Nowadays, search engines, social media or news aggregators are the preferred services for news access. Aggregation is mostly based on artificial intelligence technologies raising a new challenge: Trust has been ranked as the most important factor for media ...

Understanding everyday life behavior of young adults through personal devices, e.g., smartphones and smartwatches, is key for various applications, from enhancing the user experience in mobile apps to enabling appropriate interventions in digital health ap ...

With the increased presence of digital imaging devices there also came an explosion in the amount of multimedia content available online. Users have transformed from passive consumers of media into content creators and have started organizing themselves in ...

Introduction and Aims Drinks consumed in real life are diverse, in terms of beverage type, container size and alcohol by volume. To date, most ecological momentary assessment studies have assessed drinking amounts with 'standard' drinks, although their eve ...

Daniel Gatica-Perez

Chattez avec Graph Search

Modeling semantic aspects for cross-media image indexing

Embedding Motion in Model-Based Stochastic Tracking

Capturing drinking and nightlife behaviours and their social and physical context with a smartphone application - investigation of users' experience and reactivity

Emergent leaders through looking and speaking: from audio-visual data to multimodal recognition

Analyzing ancient Maya glyph collections with Contextual Shape Descriptors

DrinkSense: Characterizing Youth Drinking Behavior using Smartphones

Focus on People: Five Qestions from Human-Centered Computing

Your Day in Your Pocket: Complex Activity Recognition from Smartphone Accelerometers

Sensing Eating Events in Context: A Smartphone-Only Approach

Rapport with Virtual Agents: What do Human Social Cues and Personality Explain?

Special Section on Social Media as Sensors

ProGAP: Progressive Graph Neural Networks with Differential Privacy Guarantees

Estimating Dominance in Multi-Party Meetings Using Speaker Diarization

Tracking the visual focus of attention for a varying number of wandering people

Keep Sensors in Check: Disentangling Country-Level Generalization Issues in Mobile Sensor-Based Models with Diversity Scores

Development of the Geographical Proportional-to-size Street-Intercept Sampling (GPSIS) method for recruiting urban nightlife-goers in an entire city

Trust Indicators and Explainable AI: A Study on User Perceptions

DiversityOne: A Multi-Country Smartphone Sensor Dataset for Everyday Life Behavior Modeling

Modeling and Understanding Flickr Communities through Topic-based Analysis

Shooting shots: Estimating alcoholic drink sizes in real life using event-level reports and annotations of close-up pictures