| 1. |
- Anaby, D., et al.
(författare)
-
Changes in participation patterns of youth with physical disabilities following the Pathways and Resources for Engagement and Participation intervention: A time-geography approach
- 2020
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Ingår i: Scandinavian Journal of Occupational Therapy. - : Informa UK Limited. - 1103-8128 .- 1651-2014. ; 27:5, s. 364-372
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Tidskriftsartikel (refereegranskat)abstract
- Background: The PREP (Pathways and Resources for Engagement and Participation), an innovative 12-week occupational therapy intervention that focuses on changing the environment, was found effective in improving the participation of youth in specific chosen community-based activities. Objective: To complement existing evidence, this study explored changes in overall participation patterns of youth with physical disabilities following the PREP intervention. Methods: Guided by time-geography approach, 13 youth aged 12-17 completed a 24-hr diary using the Aday app during one typical weekday and another day during the weekend, pre- and post-intervention. Data of 50 diaries were plotted and analyzed using the VISUALTimePAcTS program. Results: Following the PREP, youth were engaged in less digital media and more in study-related activities. Number of occurrences and time spent doing activities with friends were greater post-intervention, whereas time spent doing activities at home was quite similar, particularly during the weekdays. During the weekends, however, youth spent slightly less time at home. Conclusions and significance: Findings provide preliminary support for the effectiveness of the PREP, extending beyond the accomplishment of specific targeted activities towards a change in the overall daily patterns of youth. Such knowledge can redirect occupational therapists' attention to environment-focused interventions involving real-life experiences.
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| 2. |
- Bernard, Jürgen, et al.
(författare)
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Foreword to Special Section on EuroVA 2021
- 2022
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Ingår i: Computers & graphics. - : Pergamon-Elsevier Science Ltd. - 0097-8493 .- 1873-7684. ; 107, s. A9-A9
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Ceccato, Vania, Professor, 1968-, et al.
(författare)
-
The situational conditions of suicide in transit environments : An analysis using CCTV footage
- 2021
-
Ingår i: Journal of Transport & Health. - : Elsevier BV. - 2214-1405 .- 2214-1413. ; 20
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: We explore the use of CCTV footage to map suicidal self-injurious behavior on a subway platform to better understand the settings and the situational conditions of individuals just before they attempt suicide. Methods: We use footage from CCTV cameras for gaining new insight into the situational conditions that relate to suicidal self-directed violence in the transit system in Stockholm, Sweden. We adopt a space-time budget template to record, step-by-step, what happens over time as individuals on the platform wait for an incoming train. The analysis applies visualization tools (VISUAL-TimePAcTS) and uses a cross-over design to identify risk factors associated with suicide. Results: Findings show that suicide risk varies both temporally and spatially. Among all types of possible behaviors and places, being close to the edge of the platform of the opposite direction of the train and crossing the security line – this behavior and place combined – are associated with increased risk of suicide. Conclusions: We confirm that using CCTV footage as data source provides valuable insight into relevant situational conditions in which suicides take place, which can be useful to inform prevention strategies, particularly information about behavior and place combined. The article concludes by reflecting upon the importance of these results for future research.
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| 4. |
- Domova, Veronika, et al.
(författare)
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A Model for Types and Levels of Automation in Visual Analytics: A Survey, a Taxonomy, and Examples
- 2023
-
Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : IEEE COMPUTER SOC. - 1077-2626 .- 1941-0506. ; 29:8, s. 3550-3568
-
Tidskriftsartikel (refereegranskat)abstract
- The continuous growth in availability and access to data presents a major challenge to the human analyst. As the manual analysis of large and complex datasets is nowadays practically impossible, the need for assisting tools that can automate the analysis process while keeping the human analyst in the loop is imperative. A large and growing body of literature recognizes the crucial role of automation in Visual Analytics and suggests that automation is among the most important constituents for effective Visual Analytics systems. Today, however, there is no appropriate taxonomy nor terminology for assessing the extent of automation in a Visual Analytics system. In this article, we aim to address this gap by introducing a model of levels of automation tailored for the Visual Analytics domain. The consistent terminology of the proposed taxonomy could provide a ground for users/readers/reviewers to describe and compare automation in Visual Analytics systems. Our taxonomy is grounded on a combination of several existing and well-established taxonomies of levels of automation in the human-machine interaction domain and relevant models within the visual analytics field. To exemplify the proposed taxonomy, we selected a set of existing systems from the event-sequence analytics domain and mapped the automation of their visual analytics process stages against the automation levels in our taxonomy.
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| 5. |
- Ellegård, Kajsa, 1951-, et al.
(författare)
-
Appliances Facilitating Everyday Life - Electricity Use Derived from Daily Activities
- 2011
-
Ingår i: Proceeding from the World Renewable Energy Congress - Sweden, 8-13 May, 2011. - : Linköping University Electronic Press. - 9789173930703 ; , s. 1031-1038
-
Konferensbidrag (refereegranskat)abstract
- The purpose of this paper is to present how, using a visualization method, electricity use can be derived from the everyday activity patterns of household members. Target groups are, on the one hand, professionals in the energy sector and energy advisors who need more knowledge about household energy use, and, on the other hand, household members wanting to reduce the energy use by revealing their own habits and thereby finding out how changed activity performance may influence electricity use. The focus is on the relation between utilizing electric appliances to perform everyday life activities and the use of electricity. The visualization method is based on the time-geographic approach developed by Hägerstrand and includes a model that estimates appliance electricity use from household members’ activities. Focus, in this paper, is put on some basic activities performed to satisfy daily life needs: cooking and use of information, communication and entertainment devices. These activities appear frequently in the everyday life of households, even though not all household members perform them all. The method is applied on a data material comprising time-diaries written by 463 individuals (aged 10 to 85+) in 179 households in different parts of Sweden. The visualization method reveals when and for how long activities that claim electric appliances are performed by which individual(s). It also shows electricity load curves generated from the use of appliances at different levels, such as individual, household and group or population levels. At household level the method can reveal which household members are the main users of electricity, i.e. the division of labour between household members. Thereby it also informs about whom could be approached by energy companies and energy advisors in information campaigns. The main result of the study is that systematic differences in activity patterns in subgroups of a population can be identified (e.g. men and women) but that directed information based on these patterns has to be made with care and with the risk of making too broad generalizations.
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| 6. |
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| 7. |
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| 8. |
- Ellegård, Kajsa, 1951-, et al.
(författare)
-
En tidsgeografisk studie av strukturen i lärares vardag
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten En tidsgeografisk studie av lärares vardag bygger på det dagboksmaterial som Skolverket samlade in under våren 2012 från drygt 3 600 lärare. Den besvarar frågor som:När under dagen utförs arbetsrelaterade aktiviteter och var utförs de?Har aktiviteterna lång eller kort varaktighet?Vilka skillnader och likheter finns mellan lärare i olika årskurser? Vilka arbetsrelaterade aktiviteter utförs efter lektionstid och var genomförs de?Finns det sekvenser av aktiviteter som återkommer hos många lärare i yrkesvardagen?I rapporten visualiseras grundskollärares tidsanvändning så att deras aktiviteter under dygnet beskrivs i den tidsordning som de genomförs.Resultatet visar att lärares arbetsvecka i mångt och mycket ser likartad ut. Det tar sig uttryck i att lärare arbetar ungefär lika långa dagar, vistas ungefär lika lång tid i skolan, genomför till viss del samma aktivitetssekvenser. De flesta arbetsrelaterade aktiviteterna genomförs i skolan, men många lärare utför också arbetsrelaterade aktiviteter på kvällstid i hemmet. Påtagliga skillnader framgår mellan veckans fyra första dagar och fredagar och mellan lärare i olika årskurser i flera olika avseenden.Lärares yrkesvardag analyseras med hjälp av de tidsgeografiska begreppen projekt och restriktioner. Lärares förvärvsarbete är ett individprojekt och detta ska passa in både i skolans organisationsprojekt (med målet att skapa förutsättningar för elevernas lärande) och i det egna hushållets organisationsprojekt (med målet att skapa ett bra liv för hushållsmedlemmarna).Skolans organisationsprojekt innebär auktoritetsrestriktioner för lärare genom att de måste följa avtal, arbeta enligt bestämda undervisningsscheman och delta i föreskrivna möten. För lärarnas del innebär bland annat schemaläggningen av undervisningen att kopplingsrestriktioner uppstår. Lärare som vill eller behöver arbeta tillsammans måste ha tidsmässiga möjligheter och någon ledig lokal för att genomföra sina gemensamma aktiviteter och då kan inte någon av dem vara schemalagd för lektioner. Kopplingsrestriktioner uppträder t ex när tätt packade scheman och högt tryck på skolans lokaler och försvårar för samarbete mellan lärare.När arbetsrelaterade aktiviteter utförs hemma på kvällstid vävs skolans organisationsprojekt in i lärarhushållets privata projekt. Det innebär att lärares individprojekt förvärvsarbete blir en kopplingsrestriktion som hindrar henne/honom från att samtidigt delta i hushållets privata projekt. Kanske skulle t ex utökad tillgång till arbetsutrymmen i skolan där aktiviteter kan utföras ostört och koncentrerat, möjliggöra för lärare att genomföra mer av sina arbetsrelaterade aktiviteter på dagtid och i skolan?Visualiseringen av den kontextuella tidsanvändningen och analysen av de kopplingsrestriktioner som uppstår i lärarnas yrkesvardag indikerar att andra former av organisering av en del arbetsrelaterade aktiviteterna skulle kunna frigöra tid för lärarnas kärnaktiviteter.
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| 9. |
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| 10. |
- Ellegård, Kajsa, 1951-, et al.
(författare)
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VISUAL-TimePAcTS/energy use : a soft ware application for visualizing energy use from activities performed
- 2010
-
Ingår i: Conference proceedings 3rd International Scientific Conference on “Energy systems with IT”. - 9789197749367 ; , s. 1-16
-
Konferensbidrag (refereegranskat)abstract
- We will present the software application VISUAL-TimePAcTS/energy use. The application shows, in a flexible way, the energy use of individuals, households, groups and whole populations which is calculated through individuals’ performed activities. Input data is diary logs for the 24 hours of the day. There are several visualizations opportunities. First, all activities performed by each individual in the population can be shown. Second, activity patterns (i.e. combinations and repetitions of activities) can be identified and represented. Third, the activities that request energy for their performance can be visualized. Fourth, “load curves” that show the power demand can be constructed, within the application, from a set of rules relating energy consumed by different appliances to performed activities requiring these appliances. We will also present principles used for doing the activity categorization (a categorization scheme), and how we hope to develop the software further. The application opens new opportunities to make use of national time use surveys.
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| 11. |
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| 12. |
- Haga, Monika, et al.
(författare)
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Visualizing Physical Activity Patterns among Community-Dwelling Older Adults : A Pilot Study
- 2018
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Ingår i: Sports. - : MDPI. - 2075-4663. ; 6:4
-
Tidskriftsartikel (refereegranskat)abstract
- Regular physical activity relates to physical and mental functioning in older people, and promoting physical activity has the potential to substantially reduce functional decline and improve well-being. Despite this, investigations of the physical activity quotient through participation in functional activities in everyday life have traditionally gained limited focus among older populations compared to leisure-time physical activity and exercise. Considering the accumulated evidence of the health benefits of low-intensity physical activity, exploring and measuring such activities in this population is highly relevant. The aim of this study was to visualize and describe older people’s physical activity patterns in daily life using a time-geographic approach in combination with the estimation of metabolic equivalents (METS). To exemplify the new method, a sample of nine retired men (65–82 years old, mean age 76.4 ± 5.8) with no homecare services from the municipality was recruited. In order to enable a visual analysis of the physical activity patterns in daily life, we developed the VISUAL-PA software, which is a visual analysis tool that includes METS to account for intensity and enables the analysis of distinct types and domains of physical activity. The VISUAL-PA software creates graphic outputs of physical activity patterns that enable the identification, visualization, and analysis of distinct types and intensities of physical activity in addition to sedentary behavior. The use of VISUAL-PA can contribute to a broader understanding of the complexity in physical activity patterns among older adults in terms of dimensions such as activity patterns and habits, domains, and intensity level. To strengthen the public health strategies that promote health and an active lifestyle, additional knowledge about physical activity patterns is necessary. Moreover, the visualization of physical activity can enable reflections on and awareness of activity habits and preferences, and thus facilitate behavior changes in older individuals.
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| 13. |
- Muthumanickam, Prithiviraj, 1987-
(författare)
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Data Abstraction and Pattern Identification in Time-series Data
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Data sources such as simulations, sensor networks across many application domains generate large volumes of time-series data which exhibit characteristics that evolve over time. Visual data analysis methods can help us in exploring and understanding the underlying patterns present in time-series data but, due to their ever-increasing size, the visual data analysis process can become complex. Large data sets can be handled using data abstraction techniques by transforming the raw data into a simpler format while, at the same time, preserving significant features that are important for the user. When dealing with time-series data, abstraction techniques should also take into account the underlying temporal characteristics. This thesis focuses on different data abstraction and pattern identification methods particularly in the cases of large 1D time-series and 2D spatio-temporal time-series data which exhibit spatiotemporal discontinuity. Based on the dimensionality and characteristics of the data, this thesis proposes a variety of efficient data-adaptive and user-controlled data abstraction methods that transform the raw data into a symbol sequence. The transformation of raw time-series into a symbol sequence can act as input to different sequence analysis methods from data mining and machine learning communities to identify interesting patterns of user behavior. In the case of very long duration 1D time-series, locally adaptive and user-controlled data approximation methods were presented to simplify the data, while at the same time retaining the perceptually important features. The simplified data were converted into a symbol sequence and a sketch-based pattern identification was then used to identify patterns in the symbolic data using regular expression based pattern matching. The method was applied to financial time-series and patterns such as head-and-shoulders, double and triple-top patterns were identified using hand drawn sketches in an interactive manner. Through data smoothing, the data approximation step also enables visualization of inherent patterns in the time-series representation while at the same time retaining perceptually important points. Very long duration 2D spatio-temporal eye tracking data sets that exhibit spatio-temporal discontinuity was transformed into symbolic data using scalable clustering and hierarchical cluster merging processes, each of which can be parallelized. The raw data is transformed into a symbol sequence with each symbol representing a region of interest in the eye gaze data. The identified regions of interest can also be displayed in a Space-Time Cube (STC) that captures both the temporal and contextual information. Through interactive filtering, zooming and geometric transformation, the STC representation along with linked views enables interactive data exploration. Using different sequence analysis methods, the symbol sequences are analyzed further to identify temporal patterns in the data set. Data collected from air traffic control officers from the domain of Air traffic control were used as application examples to demonstrate the results.
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| 14. |
- Muthumanickam, Prithiviraj, et al.
(författare)
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Identification of Temporally Varying Areas of Interest in Long-Duration Eye-Tracking Data Sets
- 2019
-
Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; , s. 87-97
-
Tidskriftsartikel (refereegranskat)abstract
- Eye-tracking has become an invaluable tool for the analysis of working practices in many technological fields of activity. Typically studies focus on short tasks and use static expected areas of interest (AoI) in the display to explore subjects’ behaviour, making the analyst’s task quite straightforward. In long-duration studies, where the observations may last several hours over a complete work session, the AoIs may change over time in response to altering workload, emergencies or other variables making the analysis more difficult. This work puts forward a novel method to automatically identify spatial AoIs changing over time through a combination of clustering and cluster merging in the temporal domain. A visual analysis system based on the proposed methods is also presented. Finally, we illustrate our approach within the domain of air traffic control, a complex task sensitive to prevailing conditions over long durations, though it is applicable to other domains such as monitoring of complex systems.
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| 15. |
- Navarra, Carlo, 1982-, et al.
(författare)
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A progressive development of a visual analysis interface of climate‑related VGI
- 2021
-
Ingår i: Environmental Earth Sciences. - : Springer. - 1866-6280 .- 1866-6299. ; 80:20
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes the progressive development of three approaches of successively increasing analytic functionality for visually exploring and analysing climate-related volunteered geographic information. The information is collected in the CitizenSensing project within which urban citizens voluntarily submit reports of site-specific extreme weather conditions, their impacts, and recommendations for best-practice adaptation measures. The work has pursued an iterative development process where the limitations of one approach have become the trigger for the subsequent ones. The proposed visual exploration approaches are: an initial map application providing a low-level data overview, a visual analysis prototype comprising three visual dashboards for more in-depth exploration, and a final custom-made visual analysis interface, the CitizenSensing Visual Analysis Interface (CS-VAI), which enables the flexible multifaceted exploration of the climate-related geographic information in focus. The approaches developed in this work are assessed with volunteered data collected in two of the CitizenSensing project’s campaigns held in the city of Norrköping, Sweden.
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| 16. |
- Navarra, Carlo, 1982-, et al.
(författare)
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Visual Exploration of Climate-Related Volunteered Geographic Information
- 2020
-
Konferensbidrag (refereegranskat)abstract
- This paper describes two approaches for visually exploring climate-related data collected within the citizen science research project, CitizenSensing. The project addresses the need of European cities and their citizens for enhanced knowledge of sitespecific conditions regarding climatic risks and adaptation measures. The visual exploration approaches discussed are: (1) a web portal enabling users to gain a low-level overview of the collected data on a map, and (2) a visual analysis tool facilitating in-depth visual data exploration in search of spatio-temporal patterns. The aim of the study is to assess and discuss the potential of such visual exploration approaches in the context of Volunteered Geographic Information.
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| 17. |
- Neset, Tina-Simone, Professor, et al.
(författare)
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AI för klimatanpassning : Hur kan nya digitala teknologier stödja klimatanpassning?
- 2024
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Tillgång till vädervarningar med information om förväntade konsekvenser av vädret är nödvändigt för god krisberedskap hos myndigheter, kommuner, näringsliv och privatpersoner. Vidareutveckling av varningssystem som fokuserar på förväntade störningar (konsekvensbaserade varningssystem) är därför en viktig komponent i samhällets hantering av klimatförändringar. Forskningsprojektet AI för klimatanpassning (AI4CA) har analyserat möjligheter och hinder med att inkludera AI-baserad text- och bildanalys som stöd till SMHI:s konsekvensbaserade vädervarningssystem och på sikt även stödja långsiktig klimatanpassning.
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| 18. |
- Nordman, Aida, et al.
(författare)
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Extraction of CD & R Work Phases from Eye-Tracking and Simulator Logs: A Topic Modelling Approach
- 2023
-
Ingår i: AEROSPACE. - : MDPI. - 2226-4310. ; 10:7
-
Tidskriftsartikel (refereegranskat)abstract
- Automation in Air Traffic Control (ATC) is gaining an increasing interest. Possible relevant applications are in automated decision support tools leveraging the performance of the Air Traffic Controller (ATCO) when performing tasks such as Conflict Detection and Resolution (CD & R). Another important area of application is in ATCOs training by aiding instructors to assess the trainees strategies. From this perspective, models that capture the cognitive processes and reveal ATCOs work strategies need to be built. In this work, we investigated a novel approach based on topic modelling to learn controllers work patterns from temporal event sequences obtained by merging eye movement data with data from simulation logs. A comparison of the work phases exhibited by the topic models and the Conflict Life Cycle (CLC) reference model, derived from post-simulation interviews with the ATCOs, indicated that there was a correspondence between the phases captured by the proposed method and the CLC framework. Another contribution of this work is a method to assess similarities between ATCOs work strategies. A first proof-of-concept application targeting the CD & R task is also presented.
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| 19. |
- Styve, Lise, et al.
(författare)
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A Visual Analytics Pipeline for the Identification and Exploration of Extreme Weather Events from Social Media Data
- 2022
-
Ingår i: Climate. - : MDPI. - 2225-1154. ; 10:11, s. 174-174
-
Tidskriftsartikel (refereegranskat)abstract
- Extreme weather events are expected to increase in frequency and intensity due to global warming. During disaster events, up-to-date relevant information is crucial for early detection and response. Recently, Twitter emerged as a potentially important source of volunteered geographic information of key value for global monitoring systems and increasing situational awareness. While research on the use of machine learning approaches to automatically detect disaster events from social media is increasing, the visualization and exploration of the identified events and their contextual data are often neglected. In this paper, we address this gap by proposing a visual analytics pipeline for the identification and flexible exploration of extreme weather events, in particular floods, from Twitter data. The proposed pipeline consists of three main steps: (1) text classification, (2) location extraction, and (3) interactive visualization. We tested and assessed the performances of four classification algorithms for classifying relevant tweets as flood-related, applied an algorithm to assign location information, and introduced a visual interface for exploring their spatial, temporal, and attribute characteristics. To demonstrate our work, we present an example use case where two independent flooding events were identified and explored. The proposed approach has the potential to support real-time monitoring of events by providing data on local impacts collected from citizens and to facilitate the evaluation of extreme weather events to increase adaptive capacity.
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| 20. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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2D and 3D Representations for Feature Recognition in Time Geographical Diary Data
- 2010
-
Ingår i: Information Visualization. - : Palgrave Macmillan Ltd. - 1473-8716 .- 1473-8724. ; 9:4, s. 263-276
-
Tidskriftsartikel (refereegranskat)abstract
- Time geographical representations are becoming a common approach to analysing spatio-temporal data. Such representations appear intuitive in the process of identifying patterns and features as paths of populations form tracks through the 3D space, which can be seen converging and diverging over time. In this article, we compare 2D and 3D representations within a time geographical visual analysis tool for activity diary data. We identify a representative task and evaluate task performance between the two representations. The results show that the 3D representation has benefits over the 2D representation for feature identification but also indicate that these benefits can be lost if the 3D representation is not carefully constructed to help the user to see them.
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| 21. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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ActiviTree: Interactive Visual Exploration of Sequences in Event-Based Data Using Graph Similarity
- 2009
-
Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1077-2626 .- 1941-0506. ; 15:6, s. 945-952
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Tidskriftsartikel (refereegranskat)abstract
- The identification of significant sequences in large and complex event-based temporal data is a challenging problem with applications in many areas of todays information intensive society. Pure visual representations can be used for the analysis, but are constrained to small data sets. Algorithmic search mechanisms used for larger data sets become expensive as the data size increases and typically focus on frequency of occurrence to reduce the computational complexity, often overlooking important infrequent sequences and outliers. In this paper we introduce an interactive visual data mining approach based on an adaptation of techniques developed for web searching, combined with an intuitive visual interface, to facilitate user-centred exploration of the data and identification of sequences significant to that user. The search algorithm used in the exploration executes in negligible time, even for large data, and so no pre-processing of the selected data is required, making this a completely interactive experience for the user. Our particular application area is social science diary data but the technique is applicable across many other disciplines.
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| 22. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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An Interactive Approach for Exploration of Flows Through Direction-Based Filtering
- 2017
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Ingår i: Journal of Geovisualization and Spatial Analysis. - : Springer. - 2509-8810 .- 2509-8829. ; 1:1-2
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Tidskriftsartikel (refereegranskat)abstract
- This paper is concerned with the representation and exploration of flows, defined as spatial interactions between geographic locations. Flows are challenging to display in a comprehensible manner due to the nature of the data, which are characterized by many crossings and overlaps leading to clutter. A number of different strategies have been suggested for addressing this problem, which commonly involve reducing the search space, aggregating the data or simplifying the representations often at the cost of information loss or distortion of spatial context. We propose an interactive approach for exploring large and highly connected networks of flows without distorting the geographical space and without losing the context overview in the process. The approach is based on a flow-specific interaction technique for filtering the data by direction, that enables an analyst to successively identify underlying spatial arrangement patterns. We illustrate our approach through exploring flows of tourists and locals in the Greater London area.
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| 23. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Behaviour-driven clustering based on event-sequence similarity metrics
- 2010
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- When analysing event data two key objectives are to first identify interesting subsequences in the data records and then to retrieve groups of records that exhibit similar behaviour. This is especially true when the focus of the exploration is the human, for example when using activity diaries to reveal sub-populations with similar behaviour, medical records to identify groups with similar medical conditions, or web sessions to find groups with similar web-surfing habits. In this paper we propose a visual exploration approach, based on sequence similarity metrics and clustering techniques, that will allow an analyst to interactively explore the distribution of sequences along event data records as well as group the results according to user-selected similarity preferences. We have identified a set of similarity metrics that are specific to event-sequences which we use as input into a clustering algorithm. The user can choose which metrics to use and assign weighting factors to them, which results in groupings that exhibit similar behaviour according to their definition of similarity and interestingness. The resulting clusters can be interactively explored in a multiple linked-view environment showing the clusters, the cluster quality, the similarity metrics and meta (background) information describing the clustered individuals in order to make comparisons within and between groups. Using such an interactive approach that considers user preferences and takes advantage of background knowledge gives a basis for enhanced analytical reasoning by providing a more complete understanding of the retrieved groupings and can lead to a more thorough analysis and accurate assessments.
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| 24. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Everyday Life Discoveries : Mining and Visualizing Activity Patterns in Social Science Diary Data
- 2007
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Ingår i: IEEE International Conference on Information Visualisation,2007. - Los Alamitos, CA, USA : IEEE. - 0769529003 ; , s. 130-138
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Konferensbidrag (refereegranskat)abstract
- The ability to identify and examine patterns of activities is a key tool for social and behavioural science. In the past this has been done by statistical or purely visual methods but automated sequential pattern analysis through sophisticated data mining and visualization tools for pattern location and evaluation can open up new possibilities for interactive exploration of the data. This paper describes the addition of a sequential pattern identification method to the visual activity-analysis tool, VISUAL-TimePAcTS, and its effectiveness in the process of pattern analysis in social science diary data. The results have shown that the method correctly identifies patterns and conveys them effectively to the social scientist in a manner that allows them quick and easy understanding of the significance of the patterns.
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| 25. |
- Vrotsou, Katerina, 1980-
(författare)
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Everyday mining : Exploring sequences in event-based data
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Event-based data are encountered daily in many disciplines and are used for various purposes. They are collections of ordered sequences of events where each event has a start time and a duration. Examples of such data include medical records, internet surfing records, transaction records, industrial process or system control records, and activity diary data.This thesis is concerned with the exploration of event-based data, and in particular the identification and analysis of sequences within them. Sequences are interesting in this context since they enable the understanding of the evolving character of event data records over time. They can reveal trends, relationships and similarities across the data, allow for comparisons to be made within and between the records, and can also help predict forthcoming events.The presented work has researched methods for identifying and exploring such event-sequences which are based on modern visualization, interaction and data mining techniques.An interactive visualization environment that facilitates analysis and exploration of event-based data has been designed and developed, which permits a user to freely explore different aspects of this data and visually identify interesting features and trends. Visual data mining methods have been developed within this environment, that facilitate the automatic identification and exploration of interesting sequences as patterns. The first method makes use of a sequence mining algorithm that identifies sequences of events as patterns, in an iterative fashion, according to certain user-defined constraints. The resulting patterns can then be displayed and interactively explored by the user.The second method has been inspired by web-mining algorithms and the use of graph similarity. A tree-inspired visual exploration environment has been developed that allows a user to systematically and interactively explore interesting event-sequences.Having identified interesting sequences as patterns it becomes interesting to further explore how these are incorporated across the data and classify the records based on the similarities in the way these sequences are manifested within them. In the final method developed in this work, a set of similarity metrics has been identified for characterizing event-sequences, which are then used within a clustering algorithm in order to find similarly behavinggroups. The resulting clusters, as well as attributes of the clusteringparameters and data records, are displayed in a set of linked views allowing the user to interactively explore relationships within these.The research has been focused on the exploration of activity diary data for the study of individuals' time-use and has resulted in a powerful research tool facilitating understanding and thorough analysis of the complexity of everyday life.
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| 26. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Exploratory visual sequence mining based on pattern-growth
- 2019
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1077-2626 .- 1941-0506. ; 25:8, s. 2597-2610
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Tidskriftsartikel (refereegranskat)abstract
- Sequential pattern mining finds applications in numerous diverging fields. Due to the problem's combinatorial nature, two main challenges arise. First, existing algorithms output large numbers of patterns many of which are uninteresting from a user's perspective. Second, as datasets grow, mining large number of patterns gets computationally expensive. There is, thus, a need for mining approaches that make it possible to focus the pattern search towards directions of interest. This work tackles this problem by combining interactive visualization with sequential pattern mining in order to create a "transparent box" execution model. We propose a novel approach to interactive visual sequence mining that allows the user to guide the execution of a pattern-growth algorithm at suitable points through a powerful visual interface. Our approach (1) introduces the possibility of using local constraints during the mining process, (2) allows stepwise visualization of patterns being mined, and (3) enables the user to steer the mining algorithm towards directions of interest. The use of local constraints significantly improves users' capability to progressively refine the search space without the need to restart computations. We exemplify our approach using two event sequence datasets; one composed of web page visits and another composed of individuals' activity sequences.
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| 27. |
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| 28. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Exploring time diaries using semi-automated activity pattern extraction
- 2009
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Ingår i: electronic International Journal of Time Use Research (eIJTUR). ; 6:1, s. 1-25
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Tidskriftsartikel (refereegranskat)abstract
- Identifying patterns of activities in time diaries in order to understand the variety of daily life in terms of combinationsof activities performed by individuals in different groups is of interest in time use research. So far, activitypatterns have mostly been identified by visually inspecting representations of activity data or by using sequencecomparison methods, such as sequence alignment, in order to cluster similar data and then extract representativepatterns from these clusters. Both these methods are sensitive to data size, pure visual methods becometoo cluttered and sequence comparison methods become too time consuming. Furthermore, the patterns identifiedby both methods represent mostly general trends of activity in a population, while detail and unexpectedfeatures hidden in the data are often never revealed. We have implemented an algorithm that searches the timediaries and automatically extracts all activity patterns meeting user-defined criteria of what constitutes a validpattern of interest for the user’s research question. Amongst the many criteria which can be applied are a timewindow containing the pattern, minimum and maximum occurrences of the pattern, and number of people thatperform it. The extracted activity patterns can then be interactively filtered, visualized and analyzed to revealinteresting insights. Exploration of the results of each pattern search may result in new hypotheses which can besubsequently explored by altering the search criteria. To demonstrate the value of the presented approach weconsider and discuss sequential activity patterns at a population level, from a single day perspective.
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| 29. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Interactive Visual Exploration of Time-Use Data
- 2006
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Ingår i: 10th IEEE International Conference on Information Visualisation. - Los Alamitos, CA, USA : IEEE Computer Society. ; , s. 93-94
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 30. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Interactive Visual Sequence Mining Based on Pattern-Growth
- 2014
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Ingår i: IEEE Conference on Visual Analytics Science and Technology (VAST). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479962273 ; , s. 285-286
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Konferensbidrag (refereegranskat)abstract
- Sequential pattern mining aims to discover valuable patterns from datasets and has a vast number of applications in various fields. Due to the combinatorial nature of the problem, the existing algorithms tend to output long lists of patterns that often suffer from a lack offocus from the user perspective. Our aim is to tackle this problemby combining interactive visualization techniques with sequential pattern mining to create a “transparent box” execution model for existing algorithms. This paper describes our first step in this direction and gives an overview of a system that allows the user to guide the execution of a pattern-growth algorithm at suitable points, through a powerful visual interface.
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| 31. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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PODD: A Portable Diary Data Collection System
- 2014
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Ingår i: AVI '14 Proceedings of the 2014 International Working Conference on Advanced Visual Interfaces. - New York : Association for Computing Machinery (ACM). - 9781450327756 ; , s. 381-382
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Konferensbidrag (refereegranskat)abstract
- Activity diaries are a powerful data source for studying the time use of individuals and for creating awareness of individuals' daily activity patterns. The presented project is concerned with the development of an easily accessible method for collecting and analyzing diary data which will be applicable across a wide range of industrial, governmental, social science and medical domains. The PODD (POrtable Diary Data collection) is composed of a smartphone application for data registration, a web interface for user registration and an administration system for configuring the application according to the focus of the data collection.
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| 32. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Seeing Beyond Statistics : Visual Exploration of Productivity on a Construction Site
- 2008
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Ingår i: Vis 2008, Visualisation. - Los Alamitos, CA, USA : IEEE Computer Society. - 9780769532714 ; , s. 37-42
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Konferensbidrag (refereegranskat)abstract
- Work on the construction site is known to be inefficient due to workers spending much time waiting for materials, transporting materials and from frequent interruptions of tasks. Studies on the construction site typically use statistical measures to analyse the sampled data about work and such measures, while very useful, can overlook important features of the data. In this paper we apply a previously developed approach, derived from Time Geographical methods, to visually represent the sampled construction productivity data and show that this method may enable the analyst to better understand the distribution of activities, and how they are interrelated and dependent upon each other.
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| 33. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Towards a Volunteered Geographic Information-Facilitated Visual Analytics Pipeline to Improve Impact-Based Weather Warning Systems
- 2023
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Ingår i: Atmosphere. - : MDPI. - 2073-4433. ; 14:7
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Tidskriftsartikel (refereegranskat)abstract
- Extreme weather events, such as flooding, are expected to increase in frequency and intensity. Therefore, the prediction of extreme weather events, assessment of their local impacts in urban environments, and implementation of adaptation measures are becoming high-priority challenges for local, regional, and national agencies and authorities. To manage these challenges, access to accurate weather warnings and information about the occurrence, extent, and impacts of extreme weather events are crucial. As a result, in addition to official sources of information for prediction and monitoring, citizen volunteered geographic information (VGI) has emerged as a complementary source of valuable information. In this work, we propose the formulation of an approach to complement the impact-based weather warning system that has been introduced in Sweden in 2021 by making use of such alternative sources of data. We present and discuss design considerations and opportunities towards the creation of a visual analytics (VA) pipeline for the identification and exploration of extreme weather events and their impacts from VGI texts and images retrieved from social media. The envisioned VA pipeline incorporates three main steps: (1) data collection, (2) image/text classification and analysis, and (3) visualization and exploration through an interactive visual interface. We envision that our work has the potential to support three processes that involve multiple stakeholders of the weather warning system: (1) the validation of previously issued warnings, (2) local and regional assessment-support documentation, and (3) the monitoring of ongoing events. The results of this work could thus generate information that is relevant to climate adaptation decision making and provide potential support for the future development of national weather warning systems.
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| 34. |
- Vrotsou, Katerina, 1980-, et al.
(författare)
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Visualizing thermal comfort in residential passive house designs
- 2021
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Ingår i: <em>Proceedings of the Twelfth ACM International Conference on Future Energy Systems</em> (<em>e-Energy '21</em>). Association for Computing Machinery, New York, NY, USA. - New York : ACM. - 9781450383332 ; , s. 412-416
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Konferensbidrag (refereegranskat)abstract
- Energy use for thermal comfort in housing accounts for a large share of total energy use in many countries. The housing sector has the potential to lower the demand for heating and cooling through better building designs, such as the passive house concept. This concept integrates building technologies, energy systems and activities performed by end-users in their everyday lives to minimise the use of external energy sources for thermal comfort. In this study we propose a methodology based on the combination of personal diary data and their in-context interactive visualization as a promising approach to study and better understand thermal comfort in private spheres. We collected activity diaries from residents in a new display city district called Vallastaden in Linköping, Sweden. Passive house designs were promoted in Vallastaden and around 10 percent of the new housing was built with this concept. Activity and thermal comfort data from the diaries were digitalised and coded. Following this the data were represented and visually explored using an adapted, for the purpose, version of a visual analysis tool.
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| 35. |
- Westin, Carl, 1982-, et al.
(författare)
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Visual Scan Patterns in Tower Control: Foundations for an Instructor Support Tool
- 2019
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Konferensbidrag (refereegranskat)abstract
- Although where to look, when, and in what order is crucial for situation awareness and task performance in tower control, instructors are lacking support systems that can help them understand operators’ visual scan behaviours. As a way forward, this paper investigates the existence and characteristics of visual scan patterns in tower control and explores a novel support tool that can help instructors in searching for and exploring these patterns. First, eye-tracking data from two controllers were collected in a high-fidelity tower simulator. Second, a workshop was conducted with three instructors to discuss specific scan patterns that can be expected in relation to the approach scenarios used in the eye-tracking data collection. Six template visual scan patterns were identified during the workshop. Finally, an interactive visual sequence mining tool was used to identify and explore instances of the template scan patterns in the recorded eye-tracking data. Four of these could be detected using the tool: runway scans, landing clearance, touchdown and landing roll, and phases of visual focus. The identification of template scan patterns provides additional insight for formalising controllers’ visual work in tower control. The ability to detect and explore visual scan patterns in the proposed tool shows promise for improving instructors’ understanding of controllers’ visual scan behaviours, and for improving training effectiveness.
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| 36. |
- Zohrevandi, Elmira, 1989-, et al.
(författare)
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Exploring Effects of Ecological Visual Analytics Interfaces on Experts' and Novices' Decision‐Making Processes : A Case Study in Air Traffic Control
- 2022
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Ingår i: Computer graphics forum (Print). - Chichester, United Kingdom : Wiley-Blackwell Publishing Inc.. - 0167-7055 .- 1467-8659. ; 41:3, s. 453-464
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Tidskriftsartikel (refereegranskat)abstract
- Operational demands in safety-critical systems impose a risk of failure to the operators especially during urgent situations. Operators of safety-critical systems learn to make decisions effectively throughout extensive training programs and many years of experience. In the domain of air traffic control, expensive training with high dropout rates calls for research to enhance novices' ability to detect and resolve conflicts in the airspace. While previous researchers have mostly focused on redesigning training instructions and programs, the current paper explores possible benefits of novel visual representations to improve novices' understanding of the situations as well as their decision-making process. We conduct an experimental evaluation study testing two ecological visual analytics interfaces, developed in a previous study, as support systems to facilitate novice decision-making. The main contribution of this paper is threefold. First, we describe the application of an ecological interface design approach to the development of two visual analytics interfaces. Second, we perform a human-in-the-loop experiment with forty-five novices within a simplified air traffic control simulation environment. Third, by performing an expert-novice comparison we investigate the extent to which effects of the proposed interfaces can be attributed to the subjects' expertise. The results show that the proposed ecological visual analytics interfaces improved novices' understanding of the information about conflicts as well as their problem-solving performance. Further, the results show that the beneficial effects of the proposed interfaces were more attributable to the visual representations than the users' expertise.
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| 37. |
- Zohrevandi, Elmira, 1989-
(författare)
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Real-Time Visual Analytics Interfaces to Strengthen Human-Automation Collaboration
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Automation in today’s world supports human operators to accomplish several tasks in limited time. With more advanced automation and autonomous systems, the hu-mans’ role is shifting from hands-on operational tasks to supervisory tasks. In complex environments such as air traffic control, supervisory tasks become difficult to manage during unexpected situations as the operator needs to have a clear understanding of various resolution strategies and their consequences and make decisions about them in a limited amount of time (i.e. within a couple of minutes). In such environments, interface designers must carefully consider how information should be presented to the operators. An improper way of presenting information could, wastefully consume operators’ cognitive resources resulting in inefficient decision-making and an increased risk of failure. By designing ecological visual analytics interfaces, this thesis addresses the problem of real-time decision-making in the domain of air traffic control. The aim of this thesis has been to apply ecological design theories to the design and evaluation of visual representations to better support controllers’ analytical capabilities and decision-making. Four novel visual analytics interfaces were designed, developed, and tested over the course of this research project. To understand how the designed visual representations affected the operators’ decision-making processes, evaluation studies with air traffic controllers as well as novices without ATC experience were conducted for two of the designed interfaces and the results were analyzed. The contribution of this thesis to the field of air traffic control and visualization design is fourfold. First, the thesis contributes knowledge on what information should be visualized and how, to achieve functional goals of conflict detection and resolution task of air traffic control. Second, evolved through a series of design studies, a final interactive visual analytics interface is proposed that visualizes information about the available solution space for solving conflict situations between airborne traffic and the traffic complexity. The interface supports controllers’ decision-making process for resolving conflicts and ability to reduce the traffic complexity. Third, the method developed for evaluating the interface designs contribute with knowledge on how interfaces tailored to safety-critical systems can be tested. Fourth, findings show that the integration of ecological interface design with the development of visual representations can shape novice and expert operators’ decision-making towards domain-specific functional goals, while allowing them to follow their own problem-solving strategies.
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