Vassilis Kostakos

Vassilis Kostakos
University of Melbourne | MSD

PhD

About

311
Publications
148,370
Reads
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7,445
Citations
Citations since 2016
158 Research Items
5529 Citations
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Introduction
Research interests: ubiquitous and pervasive computing, human-computer interaction, social and dynamic networks
Additional affiliations
October 2011 - present
University of Oulu
Position
  • Professor
January 2008 - September 2011
Universidade da Madeira
Position
  • Professor (Assistant)
January 2008 - September 2011
Carnegie Mellon University
Position
  • Research Assistant

Publications

Publications (311)
Article
Full-text available
What mechanism links climate change and social change? Palaeoanthropological analysis of human remains suggests that abrupt climate change is linked to societal restructuring, but it has been challenging to reliably identify the exact mechanisms underlying this relationship. Here we identify one potential mechanism that can link climate to behavior...
Article
Full-text available
We present a mobile instrumentation toolkit, AWARE, an open-source effort to develop an extensible and reusable platform for capturing, inferring, and generating context on mobile devices. Mobile phones are sensor-rich but resource-constrained, and therefore several considerations need to be addressed when creating a research tool that ensures prob...
Article
Full-text available
This paper makes contributions toward adopting a systemic view of city-wide ubiquitous systems. Here, we present methods and techniques for combining multiple sensing modalities to measure and model traffic patterns in urban environments. We show how noise in one modality can be reduced by considering another more reliable modality and how two moda...
Article
Smart speakers have become exceedingly popular and entered many people's homes due to their ability to engage users with natural conversations. Researchers have also looked into using smart speakers as an interface to collect self-reported health data through conversations. Responding to surveys prompted by smart speakers requires users to listen t...
Article
Full-text available
Due to their widespread adoption, frequent use, and diverse sensor capabilities, smartphones have become a powerful tool for academic studies focused on sampling human behaviour. While packing many technological advances, the need for researchers to develop their own software packages in order to run smartphone-based studies has resulted in a clear...
Article
Emotion has long been acknowledged as an important part of technology user experience. More recently, research has begun to catalogue ways in which people use technology to manage and shape emotion. These have been characterised as emerging digital forms of a category of behaviour known to psychologists as emotion regulation. Since digital emotion...
Article
Smartphone use has become an indispensable aspect of daily life for billions of people. Increasingly, researchers are examining the impact of smartphone use upon psychological well-being. However, little research has investigated how people deliberately use their smartphones to shape affective states; in other words, how smartphones are used as too...
Chapter
Hand hygiene can reduce the transmission of pathogens and prevent healthcare-associated infections. Ultraviolet (UV) test is an effective tool for evaluating and visualizing hand hygiene quality during medical training. However, due to various hand shapes, sizes, and positions, systematic documentation of the UV test results to summarize frequently...
Preprint
Edge and Fog computing paradigms utilise distributed, heterogeneous and resource-constrained devices at the edge of the network for efficient deployment of latency-critical and bandwidth-hungry IoT application services. Moreover, MicroService Architecture (MSA) is increasingly adopted to keep up with the rapid development and deployment needs of th...
Article
Full-text available
The World Health Organization (WHO) recommends a six-step hand hygiene technique. Although multiple studies have reported that this technique yields inadequate skin coverage outcomes, they have relied on manual labeling that provided low-resolution estimations of skin coverage outcomes. We have developed a computational system to precisely quantify...
Article
Non-invasive inspection and imaging techniques are used to acquire non-visible information embedded in samples. Typical applications include medical imaging, defect evaluation, and electronics testing. However, existing methods have specific limitations, including safety risks ( e.g. , X-ray), equipment costs ( e.g. , optical tomography), personnel...
Conference Paper
Emotion has been studied in HCI for two decades, with specific traditions interested in sensing, expressing, transmitting, modelling, experiencing, visualizing, understanding, constructing, regulating, manipulating or adapting to emotion in human-human and human-computer interactions. This CHI 2022 workshop on the Future of Emotion in Human-Compute...
Article
Technology plays an increasingly prominent role in emotional lives. Researchers have begun to study how people use devices to cope with and shape emotions: a phenomenon that has been called Digital Emotion Regulation. We report a study of the impact of the COVID-19 pandemic upon young people's digital habits and emotion regulation behaviors. We con...
Article
Quality improvement methods are essential to gathering high-quality crowdsourced data, both for research and industry applications. A popular and broadly applicable method is task assignment that dynamically adjusts crowd workflow parameters. In this survey, we review task assignment methods that address: heterogeneous task assignment, question ass...
Article
The Fog computing paradigm, offering cloud-like services at the edge of the network, has become a feasible model to support computing and storage capabilities required by latency-sensitive and bandwidth-hungry Internet of Things (IoT) applications. As fog devices are distributed, heterogeneous and resource-constrained, efficient application schedul...
Article
Voice assistants, such as Amazon's Alexa and Google Home, increasingly find their way into consumer homes. Their functionality, however, is currently limited to being passive answer machines rather than proactively engaging users in conversations. Speakers' proactivity would open up a range of important application scenarios, including health servi...
Preprint
Full-text available
We present UbiNIRS, a software framework for rapid development and deployment of applications using miniaturized near-infrared spectroscopy (NIRS). NIRS is an emerging material sensing technology that has shown a great potential in recent work from the HCI community such as in situ pill testing. However, existing methods require significant program...
Preprint
Full-text available
We present a technique to embed information invisible to the eye inside 3D printed objects. The information is integrated in the object model, and then fabricated using off-the-shelf dual-head FDM (Fused Deposition Modeling) 3D printers. Our process does not require human intervention during or after printing with the integrated model. The informat...
Preprint
Quality improvement methods are essential to gathering high-quality crowdsourced data, both for research and industry applications. A popular and broadly applicable method is task assignment that dynamically adjusts crowd workflow parameters. In this survey, we review task assignment methods that address: heterogeneous task assignment, question ass...
Article
Full-text available
Social conformity is the act of individuals adjusting their personal opinions to agree with an opposing majority. Previous work has identified multiple determinants of social conformity in controlled laboratory studies, but they remain largely untested in naturalistic online environments. For this study, we developed a realistic debating website, w...
Conference Paper
The global pandemic and the uncertainty if and when life will return to normality have motivated a series of studies on human mental health. This research has elicited evidence for increasing numbers of anxiety, depression, and overall impaired mental well-being. But, the global COVID-19 pandemic has also created new opportunities for research into...
Article
Emotions have a significant impact on our decision-making, learning, awareness, social interactions, and mental and physical health. Even though large efforts have been put into quantifying human emotions, their subjectivity, context-dependence, and complexity render them as being almost unpredictable. However, while different streams of research i...
Chapter
Full-text available
Social conformity is the act of individuals adjusting personal judgements to conform to expectations of opposing majorities in group settings. While conformity has been studied in online groups with emphasis on its contextual determinants (e.g., group size, social presence, task objectivity), the effect of age – of both the individual and the membe...
Article
Background: Although convenient and reliable modern messaging apps like WhatsApp enable efficient communication among hospital staff, hospitals are now pivoting toward purpose-built structured communication apps for various reasons, including security and privacy concerns. However, there is limited understanding of how we can examine and improve h...
Article
Crowdsourced labor markets represent a powerful new paradigm for accomplishing work. Understanding the motivating factors that lead to high quality work could have significant benefits. However, researchers have so far found that motivating factors such as increased monetary reward generally increase workers’ willingness to accept a task or the spe...
Chapter
Full-text available
The Experience Sampling Method is used to collect participant self-reports over extended observation periods. These self-reports offer a rich insight into the individual lives of study participants by intermittently asking participants a set of questions. However, the longitudinal and repetitive nature of this sampling approach introduces a variety...
Preprint
Full-text available
Background: Young people are vulnerable to experiencing problematic levels of loneliness which can lead to poor mental health outcomes. Loneliness is a malleable treatment target and preliminary evidence has shown that it can be addressed with digital platforms. Peer Tree is a strengths-based digital smartphone application aimed at reducing lonelin...
Article
Full-text available
Despite large investments in smartwatch development, the market growth remains smaller than forecasted. The purpose of smartwatch use remains unclear, indicated by the lack of large-scale adoption. Thus, we aim to better understand the early adoption and everyday smartwatch use. We investigate a diverse usage data of smartwatches logged over a peri...
Article
With the wide expansion of distributed learning environments the way we learn became more diverse than ever. This poses an opportunity to incorporate different data sources of learning traces that can offer broader insights into learner behavior and the intricacies of the learning process. We argue that combining analytics across different e-learni...
Article
Full-text available
In this paper, we investigate the feasibility of using mobility patterns and demographic data to predict hospital visits. We collect mobility traces from two thousand users for around two months. We extract 16 mobility features from these passively collected mobility traces and train an XGBoost model to predict users' hospital visits. We demonstrat...
Preprint
BACKGROUND Although convenient and reliable modern messaging apps like WhatsApp enable efficient communication among hospital staff, hospitals are now pivoting toward purpose-built structured communication apps for various reasons, including security and privacy concerns. However, there is limited understanding of how we can examine and improve hos...
Article
Full-text available
Background: Hand hygiene is one of the most effective ways of preventing health care–associated infections and reducing their transmission. Owing to recent advances in sensing technologies, electronic hand hygiene monitoring systems have been integrated into the daily routines of health care workers to measure their hand hygiene compliance and qual...
Preprint
Full-text available
BACKGROUND Hand hygiene is one of the most effective ways of preventing health care–associated infections and reducing their transmission. Owing to recent advances in sensing technologies, electronic hand hygiene monitoring systems have been integrated into the daily routines of health care workers to measure their hand hygiene compliance and quali...
Article
Full-text available
In the context of learning systems, identifying causal relationships among information presented to the user, their behavior and cognitive effort required/exerted to understand and perform a task is key to building effective learning experiences, and to maintain engagement in learning processes. An unexplored question is whether our interaction wit...
Article
NIRS is a spectroscopic method that propagates near-infrared waves through objects and measures the absorbance by diffuse reflection, users could analyze the composition information of objects based on that. The technology has fast speed and non-destructive analysis features with relatively simple requirements for operators, making it very friendly...
Article
Full-text available
Background The use of location-based data in clinical settings is often limited to real-time monitoring. In this study, we aim to develop a proximity-based localization system and show how its longitudinal deployment can provide operational insights related to staff and patients' mobility and room occupancy in clinical settings. Such a streamlined...
Article
Full-text available
While crowd workers typically complete a variety of tasks in crowdsourcing platforms, there is no widely accepted method to successfully match workers to different types of tasks. Researchers have considered using worker demographics, behavioural traces, and prior task completion records to optimise task assignment. However, optimum task assignment...
Conference Paper
Full-text available
Although crowd work is typically completed through desktop or laptop computers by workers at their home, literature has shown that crowdsourcing is feasible through a wide array of computing devices, including smartphones and digital voice assistants. An integrated crowdsourcing platform that operates across multiple devices could provide greater f...
Article
Full-text available
A catalyst for the spread of fake news is the existence of comments that users make in support of, or against, such articles. In this study we investigate whether critical and supportive comments can induce conformity in how readers perceive trustworthiness of news articles and respond to them. We find that individuals tend to conform to the majori...
Article
Full-text available
Recent years have witnessed much work unraveling human mobility patterns through urban visitation and location check-in data. Traditionally, user visitation and check-in have been assumed as the same behavior, yet this fundamental assumption can be questionable and lacks supporting evidence. In this paper, we seek to understand the similarities and...
Article
Although crowd work is typically completed through desktop or laptop computers by workers at their home, literature has shown that crowdsourcing is feasible through a wide array of computing devices, including smartphones and digital voice assistants. An integrated crowdsourcing platform that operates across multiple devices could provide greater f...
Article
Full-text available
Sensing and machine learning advances have enabled the unobtrusive measurement of physiological responses and facial expressions so as to estimate one's cognitive performance. This often boils down to mapping the states of the cognitive processes underpinning human cognition: physiological responses (e.g., heart rate) and facial expressions (e.g.,...
Article
The articles in this special section focus on personalized pervasive health. For over more than two decades, mobile, wearable, and ambient sensor and interaction devices have grown into today’s plethora of computing platforms and tools for pervasive health. Pervasive computing is now assimilating into medicine, from disease risk prevention to diagn...
Conference Paper
Kinship verification is the problem whereby a third party determines whether two people are related. Despite previous research in Psychology and Machine Vision, the factors affecting a person's verification ability are poorly understood. Through an online crowdsourcing study, we investigate the impact of gender, race and medium type (image vs video...
Article
Physical, mental, and behavioral processes of most living beings underlie cyclic changes, mainly governed by the day-night cycle. Investigations of these circadian rhythms have traditionally required constrained settings and invasive methods, such as repetitive blood testing and testing in sleep laboratories. Recent developments in pervasive techno...
Article
Full-text available
Social conformity occurs when individuals in group settings change their personal opinion to be in agreement with the majority's position. While recent literature frequently reports on conformity in online group settings, the causes for online conformity are yet to be fully understood. This study aims to understand how social presencei.e., the sens...
Preprint
BACKGROUND The use of location-based data in clinical settings is often limited to real-time monitoring. Here we develop a proximity-based localisation system, and show how its longitudinal analysis can provide operational insights relating to mobility and occupancy in clinical settings. OBJECTIVE We measure the accuracy of the system, and algorit...
Conference Paper
Full-text available
Inspired by the increasing prevalence of digital voice assistants, we demonstrate the feasibility of using voice interfaces to deploy and complete crowd tasks. We have developed Crowd Tasker, a novel system that delivers crowd tasks through a digital voice assistant. In a lab study, we validate our proof-of-concept and show that crowd task performa...
Article
Full-text available
Purpose The purpose of this paper is to propose a distributed smartphone sensing-enabled system, which assumes an intelligent transport signaling (ITS) infrastructure that operates traffic lights in a smart city (SC). The system is able to handle priorities between groups of cyclists (crowd-cycling) and traffic when approaching traffic lights at ro...
Article
Full-text available
Equipped with an abundance of small-scale microelectromechanical sensors, modern mobile devices such as smartphones and smartwatches can now offer context-aware services to users in mobile environments. Although advances in mobile context-aware applications have made our everyday environments increasingly intelligent, these applications are prone t...
Article
Despite decades of research concerning social conformity and its effects on face-to-face groups, it is yet to be comprehensively investigated in online contexts. In our work, we investigate the impact of contextual determinants (such as majority group size, the number of opposing minorities and their sizes, and the nature of the task) and personal...