Abdallah El Ali

Centrum Wiskunde & Informatica | CWI · Research Group for Distributed and Interactive Systems

One way to indicate nonverbal cues is by sending emoji (e.g., 😂), which requires users to make a selection from large lists. Given the growing number of emojis, this can incur user frustration, and instead we propose Face2Emoji, where we use a user's facial emotional expression to filter out the relevant set of emoji by emotion category. To validat...

Voice is a rich modality for conveying emotions, however emotional prosody production can be situationally or medically impaired. Since thermal displays have been shown to evoke emotions, we explore how thermal stimulation can augment perception of neutrally-spoken voice messages with affect. We designed ThermalWear, a wearable on-chest thermal dis...

Collecting accurate and precise emotion ground truth labels for mobile video watching is essential for ensuring meaningful predictions. However, video-based emotion annotation techniques either rely on post-stimulus discrete self-reports, or allow real-time, continuous emotion annotations (RCEA) only for desktop settings. Following a user-centric a...

Watching 360 videos using Virtual Reality (VR) head-mounted displays (HMDs) provides interactive and immersive experiences, where videos can evoke different emotions. Existing emotion self-report techniques within VR however are either retrospective or interrupt the immersive experience. To address this, we introduce the Continuous Physiological an...

Visualizing biosignals can be important for social Virtual Reality (VR), where avatar non-verbal cues are missing. While several biosignal representations exist, designing effective visualizations and understanding user perceptions within social VR entertainment remains unclear. We adopt a mixed-methods approach to design biosignals for social VR e...

Recently, we saw a trend toward using physiological signals in interactive systems. These signals, offering deep insights into users' internal states and health, herald a new era for HCI. However, as this is an interdisciplinary approach, many challenges arise for HCI researchers, such as merging diverse disciplines, from understanding physiologica...

Measuring interoception (‘perceiving internal bodily states’) has diagnostic and wellbeing implications. Since heartbeats are distinct and frequent, various methods aim at measuring cardiac interoceptive accuracy (CIAcc). However, the role of exteroceptive modalities for representing heart rate (HR) across screen-based and Virtual Reality (VR) envi...

During group interactions, we react and modulate our emotions and behaviour to the group through phenomena including emotion contagion and physiological synchrony. Previous work on emotion recognition through video/image has shown that group context information improves the classification performance. However, when using physiological data, literat...

In what capacity are affective augmentations helpful to humans, and what risks (if any) do they pose? In this position paper, we outline three works on affective augmentation systems, where our studies suggest these systems have the ability to influence our cognitive, affective, and (social) bodily perceptions in perhaps unusual ways. We provide co...

In this position paper, we outline our research challenges in Affective Interactive Systems, and present recent work on visualizing avatar biosignals for social VR entertainment. We highlight considerations for how biosignals animations in social VR spaces can (falsely) indicate users' availability status.

Social VR enables people to interact over distance with others in real-time. It allows remote people, typically represented as avatars, to communicate and perform activities together in a shared virtual environment, extending the capabilities of traditional social platforms like Facebook and Netflix. This paper explores the benefits and drawbacks p...

Instead of predicting just one emotion for one activity (e.g., video watching), fine-grained emotion recognition enables more temporally precise recognition. Previous works on fine-grained emotion recognition require segment-by-segment, fine-grained emotion labels to train the recognition algorithm. However, experiments to collect these labels are...

Fine-grained emotion recognition can model the temporal dynamics of emotions, which is more precise than predicting one emotion retrospectively for an activity (e.g., video clip watching). Previous works require large amounts of continuously annotated data to train an accurate recognition model, how- ever experiments to collect such large amounts o...

Inferring emotions from Head Movement (HM) and Eye Movement (EM) data in 360° Virtual Reality (VR) can enable a low-cost means of improving users’ Quality of Experience. Correlations have been shown between retrospective emotions and HM, as well as EM when tested with static 360° images. In this early work, we investigate the relationship between m...

Precise emotion ground truth labels for 360° virtual reality (VR) video watching are essential for fine-grained predictions under varying viewing behavior. However, current annotation techniques either rely on post-stimulus discrete self-reports, or real-time, continuous emotion annotations (RCEA) but only for desktop/mobile settings. We present RC...

Social VR enables people to interact over distance with others in real-time. It allows remote people, typically represented as avatars, to communicate and perform activities together in a join shared virtual environment, extending the capabilities of traditional social platforms like Facebook and Netflix. This paper explores the benefits and drawba...

Segregation often dismantles common activity spaces and isolates people of different backgrounds, leading to irreconcilable inequalities that disfavour the poor and minorities and intensifies societal fragmentation. Therefore, segregation has become an increasing concern and topic of research with studies typically concentrating on the residential...

Recognizing user emotions while they watch short-form videos anytime and anywhere is essential for facilitating video content customization and personalization. However, most works either classify a single emotion per video stimuli, or are restricted to static, desktop environments. To address this, we propose a correlation-based emotion recognitio...

With the increasing availability of head-mounted displays (HMDs) that show immersive 360 • VR content, it is important to understand to what extent these immersive experiences can evoke emotions. Typically to collect emotion ground truth labels, users rate videos through post-experience self-reports that are discrete in nature. However, post-stimul...

Recognizing human emotions and responding appropriately has the potential to radically change the way we interact with technology. However, to train machines to sensibly detect and recognize human emotions, we need valid emotion ground truths. A fundamental challenge here is the momentary emotion elicitation and capture (MEEC) from individuals cont...

Segregation often dismantles common activity spaces and isolates people of different backgrounds, leading toirreconcilable inequalities that disfavour the poor and minorities and intensifies societal fragmentation. Therefore,segregation has become an increasing concern and topic of research with studies typically concentratingon the residential com...

To recognize emotions using less obtrusive wearable sensors, we present a novel emotion recognition method that uses only pupil diameter (PD) and skin conductance (SC). Psychological studies show that these two signals are related to the attention level of humans exposed to visual stimuli. Based on this, we propose a feature extraction algorithm th...

Biometric techniques can help make vehicles safer to drive, authenticate users, and provide personalized in-car experiences. However, it is unclear to what extent users are willing to trade their personal biometric data for such benefits. In this early work, we conducted an open card sorting study (N=11) to better understand how well users perceive...

Current techniques for tracking sleep are either obtrusive (Polysomnography) or low in accuracy (wearables). In this early work, we model a sleep classification system using an unobtrusive Ballistocardiographic (BCG)-based heart sensor signal collected from a commercially available pressure-sensitive sensor sheet. We present DeepSleep, a hybrid dee...

Millions of photos are shared online daily, but the richness of interaction compared with face-to-face (F2F) sharing is still missing. While this may change with social Virtual Reality (socialVR), we still lack tools to measure such immersive and interactive experiences. In this paper, we investigate photo sharing experiences in immersive environme...

Navigation systems for cyclists are commonly screen-based devices mounted on the handlebar which show map information. Typically, adult cyclists have to explicitly look down for directions. This can be distracting and challenging for children, given their developmental differences in motor and perceptual-motor abilities compared with adults. To add...

Current asynchronous (e. g., email) or synchronous (e. g., video-conferencing) communication methods in the workspace can be obtrusive and fail to mimic spontaneous interpersonal communication. This can cause difficulties in forming close relationships among working colleagues. To examine this problem, we conducted a needs assessment study consisti...

High-level APIs such as Keras facilitate the development of deep learning models through a simple interface and enable users to train neural networks within a few lines of code. Building on top of TensorFlow, trained models can be exported and run efficiently on mobile devices. This enables a wide range of opportunities for researchers and develope...

Head-mounted devices (HMDs) for Virtual and Augmented Reality (VR/AR) enable us to alter our visual perception of the world. However, current devices suffer from a limited field of view (FOV), which becomes problematic when users need to locate out of view objects (e.g., locating points-of-interest during sightseeing). To address this, we developed...

Current head-mounted displays (HMDs) for Virtual Reality (VR) and Augmented Reality (AR) have a limited field-of-view (FOV). This limited FOV further decreases the already restricted human visual range and amplifies the problem of objects going out of view. Therefore, we explore the utility of augmenting HMDs with RadialLight, a peripheral light di...

Systematische Literaturrecherchen stellen in den Gesundheitswissenschaften ein wichtiges Instrument zur Beurteilung des Forschungsstandes dar. Durch den stark zunehmenden Bestand an verfügbarer Literatur sind bei Wahrung anerkannter wissenschaftlicher Standards hohe zeitliche und personelle Ressourcen zur Durchführung dieser Literaturanalysen notwe...

This paper investigates bias in coverage between Western and Arab media on Twitter after the November 2015 Beirut and Paris terror attacks. Using two Twitter datasets covering each attack, we investigate how Western and Arab media differed in coverage bias, sympathy bias, and resulting information propagation. We crowdsourced sympathy and sentiment...

Head-mounted displays allow user to augment reality or dive into a virtual one. However, these 3D spaces often come with problems due to objects that may be out of view. Visualizing these out-of-view objects is useful under certain scenarios, such as situation monitoring during ship docking. To address this, we designed a lo-fi prototype of our Eye...

Various off-screen visualization techniques that point to off-screen objects have been developed for small screen devices. A similar problem arises with head-mounted Augmented Reality (AR) with respect to the human field-of-view, where objects may be out of view. Being able to detect so-called out-of-view objects is useful for certain scenarios (e....

Innovations often trigger objections before becoming widely accepted. This paper assesses whether a familiarisation over time can be expected for data glasses, too. While user attitudes towards those devices have been reported to be prevalently negative [14], it is still unclear, to what extent this initial, negative user attitude might impede adop...

Activity trackers are frequently used in health and well-being, but their application in effective interventions is challenging. While research for reasons of use and non-use is ongoing, little is known about the way activity trackers are used in everyday life and over longer periods. We analyzed data of 104 individuals over 14,413 use days, and in...

The increasing amount of in-vehicle information systems has led to handling multiple tasks simultaneously. This increases mental workload and consequently causes interruptions and distraction from driving. In this paper, we propose applying peripheral light cues to support in-vehicle task resumption. We ran a driving simulator study in which we tes...

The DIY rollable soundboard is a paper-based instant button device, driven by a Raspberry Pi that allows for easily creating simple sound effects. With sound effects like a Badum Tss (the sound of drums which often appears for a bad joke in comedy shows), it augments everyday situations with a suitable sound while users are on the go. Since paper i...

While HCI for development (HCI4D) research has typically focused on technological practices of poor and low-literate communities, little research has addressed how technology literate individuals living in a poor infrastructure environment use technology. Our work fills this gap by focusing on Lebanon, a country with longstanding political instabil...

Car navigation systems typically combine multiple output modalities; for example, GPS-based navigation aids show a real-time map, or feature spoken prompts indicating upcoming maneuvers. However, the drawback of graphical navigation displays is that drivers have to explicitly glance at them, which can distract from a situation on the road. To decre...

Despite current controversy over e-cigarettes as a smoking cessation aid, we present early work based on a web survey (N=249) that shows that some e-cigarette users (46.2%) want to quit altogether, and that behavioral feedback that can be tracked can fulfill that purpose. Based on our survey findings, we designed VapeTracker, an early prototype tha...

Balancing usability and security in user authentication is essential to the adoption of any authentication method. Magnet-based Around Device Interaction (ADI), in allowing 3D gestural signatures around the device, has been shown to be a secure method for user authentication. In this paper, we further verify the usability and security of this metho...

This paper presents the motivation, design and evaluation of CountMeIn, a mobile collaborative pervasive memory game to revive social interactions in public places (e.g. a train station or bus stop). Two versions of CountMeIn were tested; an NFC-based and a touchscreen version. In a 2x1 within-subject (NFC vs. Touch) experiment (N = 20), postexperi...

Around Device Interaction ADI has expanded the interaction space on mobile devices to allow 3D gesture interaction around the device. In this paper, the authors look specifically at magnet-based ADI and its applied use in a playful, music-related context. Using three musical applications developed under the magnet-based ADI paradigm Air Disc-Jockey...

Using Location-aware Multimedia Messaging (LMM) systems as a research testbed, this paper presents an analysis of how ‘fun or playfulness’ can be studied and designed for under mobile and ubiquitous environments. These LMM systems allow users to leave geo-tagged multimedia messages behind at any location. Drawing on previous efforts with LMM system...

This paper presents the motivation, design, and pilot evaluation of CountMeIn, a pervasive collaborative game to improve the waiting time experience (e.g., waiting for a train, or traffic light to turn green). We tested two versions of CountMeIn, an NFC-based and touchscreen version in a small pilot study. Our early results showed that the NFC-base...

Urban mobility analysis of geotagged photos can unlock mobility patterns of users who took these photos, which can be used for exploration-based city route planners. Applying sequence alignment techniques on 5 years of geotagged Flickr photos in Amsterdam (The Netherlands) allowed creating walkable city routes based on paths traversed by multiple p...

In the last 20 years, the widespread adoption of personal, mobile computing devices in everyday life, has allowed entry into a new technological era in Human Computer Interaction (HCI). The constant change of the physical and social context in a user's situation made possible by the portability of mobile devices means that the user's attention beco...

The aim of this work is three-fold: first, to provide a brief historical ac- count of time in cognitive psychology focusing primarily on the significant contributions of Jean-Marie Guyau, William James, and Henri Bergson. In examining the historical ideas of these influential writers, the present work hopes to furnish the psychology of time with a...

While gesture taxonomies provide a classification of device-based gestures in terms of communicative intent, little work has addressed the usability differences in manually performing these gestures. In this primarily qualitative study, we investigate how two sets of iconic gestures that vary in familiarity, mimetic and alphabetic, are affected und...

This paper describes a field study evaluating a mobile map application for the Paris Air Show. The aim of the study was to investigate how well users can navigate (to static and moving targets) and orient themselves in a fair (an unknown environment posing realistic challenges for wayfinding) with a mobile map system. The study involved 14 fair vis...

In this paper, we are concerned with how a real-world social situation shapes the interaction with a novel technology that combines collocated mobile phone and public display use for groups of people. We present a user study of a system that allows collaborative creation and sharing of comic strips on public displays in a social setting such as a p...