Kai Xu

Prof. Kai Xu

Middlesex University
orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 June 2020 in Computer Graphics Forum
Verified
Journal Article
Closed access
PDF file
Kai XuKai Xu
Kai Xu
AOAlvitta Ottley
Alvitta Ottley
CWConny Walchshofer
Conny Walchshofer
MSMarc Streit
Marc Streit
RCRemco Chang
Remco Chang
JWJohn Wenskovitch
John Wenskovitch

22 May 2015 in IEEE Computer Graphics and Applications
Verified
Journal Article
Closed access
Kai XuKai Xu
Kai Xu
SASimon Attfield
Simon Attfield
TJT.J. Jankun-Kelly
T.J. Jankun-Kelly
AWAshley Wheat
Ashley Wheat
PNPhong Nguyen
Phong Nguyen
NSNallini Selvaraj
Nallini Selvaraj
Sensemaking is a process of finding meaning from information that often involves activities such as information foraging and hypothesis generation. It can be valuable to maintain a history of the data and reasoning involved. This history, commonly known as provenance information, can be a resource for "reflection-in-action"' during analysis, supporting collaboration between analysts, and can help trace data quality and uncertainty through the analysis process. Currently, there is limited work on utilizing analytic provenance, which captures the interactive data exploration and human reasoning process, to support sensemaking. This article presents and extends the research challenges discussed in a IEEE VIS 2014 workshop on this topic to provide an agenda for sensemaking analytic provenance.

9 October 2012 in IEEE Transactions on Visualization and Computer Graphics
Verified
Journal Article
Closed access
Kai XuKai Xu
Kai Xu
CRChris Rooney
Chris Rooney
PPPeter Passmore
Peter Passmore
DHDong-Han Ham
Dong-Han Ham
PNPhong Nguyen
Phong Nguyen
Recently there has been increasing research interest in displaying graphs with curved edges to produce more readable visualizations. While there are several automatic techniques, little has been done to evaluate their effectiveness empirically. In this paper we present two experiments studying the impact of edge curvature on graph readability. The goal is to understand the advantages and disadvantages of using curved edges for common graph tasks compared to straight line segments, which are the conventional choice for showing edges in node-link diagrams. We included several edge variations: straight edges, edges with different curvature levels, and mixed straight and curved edges. During the experiments, participants were asked to complete network tasks including determination of connectivity, shortest path, node degree, and common neighbors. We also asked the participants to provide subjective ratings of the aesthetics of different edge types. The results show significant performance differences between the straight and curved edges and clear distinctions between variations of curved edges.

23 March 2017
Verified
Conference Paper
Closed access
PNPhong Nguyen
Phong Nguyen
Kai XuKai Xu
Kai Xu
ABAndy Bardill
Andy Bardill
BSBetul Salman
Betul Salman
KHKate Herd
Kate Herd
BWB.L. William Wong
B.L. William Wong
Sensemaking is described as the process in which people collect, organize and create representations of information, all centered around some problem they need to understand. People often get lost when solving complicated tasks using big datasets over long periods of exploration and analysis. They may forget what they have done, are unaware of where they are in the context of the overall task, and are unsure where to continue. In this paper, we introduce a tool, SenseMap, to address these issues in the context of browser-based online sensemaking. We conducted a semi-structured interview with nine participants to explore their behaviors in online sensemaking with existing browser functionality. A simplified sensemaking model based on Pirolli and Card's model is derived to better represent the behaviors we found: users iteratively collect information sources relevant to the task, curate them in a way that makes sense, and finally communicate their findings to others. SenseMap automatically captures provenance of user sensemaking actions and provides multi-linked views to visualize the collected information and enable users to curate and communicate their findings. To explore how SenseMap is used, we conducted a user study in a naturalistic work setting with five participants completing the same sensemaking task related to their daily work activities. All participants found the visual representation and interaction of the tool intuitive to use. Three of them engaged with the tool and produced successful outcomes. It helped them to organize information sources, to quickly find and navigate to the sources they wanted, and to effectively communicate their findings.

13 August 2015 in IEEE Transactions on Visualization and Computer Graphics
Verified
Journal Article
Closed access
PNPhong Nguyen
Phong Nguyen
Kai XuKai Xu
Kai Xu
AWAshley Wheat
Ashley Wheat
BWB.L. William Wong
B.L. William Wong
SASimon Attfield
Simon Attfield
BFBob Fields
Bob Fields
Sensemaking is described as the process of comprehension, finding meaning and gaining insight from information, producing new knowledge and informing further action. Understanding the sensemaking process allows building effective visual analytics tools to make sense of large and complex datasets. Currently, it is often a manual and time-consuming undertaking to comprehend this: researchers collect observation data, transcribe screen capture videos and think-aloud recordings, identify recurring patterns, and eventually abstract the sensemaking process into a general model. In this paper, we propose a general approach to facilitate such a qualitative analysis process, and introduce a prototype, SensePath, to demonstrate the application of this approach with a focus on browser-based online sensemaking. The approach is based on a study of a number of qualitative research sessions including observations of users performing sensemaking tasks and post hoc analyses to uncover their sensemaking processes. Based on the study results and a follow-up participatory design session with HCI researchers, we decided to focus on the transcription and coding stages of thematic analysis. SensePath automatically captures user's sensemaking actions, i.e., analytic provenance, and provides multi-linked views to support their further analysis. A number of other requirements elicited from the design session are also implemented in SensePath, such as easy integration with existing qualitative analysis workflow and non-intrusive for participants. The tool was used by an experienced HCI researcher to analyze two sensemaking sessions. The researcher found the tool intuitive and considerably reduced analysis time, allowing better understanding of the sensemaking process.

3 June 2024 in IEEE Transactions on Visualization and Computer Graphics
Verified
Journal Article
Closed access
YGYuhan Guo
Yuhan Guo
HSHanning Shao
Hanning Shao
CLCan Liu
Can Liu
Kai XuKai Xu
Kai Xu
XYXiaoru Yuan
Xiaoru Yuan
Generative text-to-image models, which allow users to create appealing images through a text prompt, have seen a dramatic increase in popularity in recent years. However, most users have a limited understanding of how such models work and often rely on trial and error strategies to achieve satisfactory results. The prompt history contains a wealth of information that could provide users with insights into what has been explored and how the prompt changes impact the output image, yet little research attention has been paid to the visual analysis of such process to support users. We propose the Image Variant Graph, a novel visual representation designed to support comparing prompt-image pairs and exploring the editing history. The Image Variant Graph models prompt differences as edges between corresponding images and presents the distances between images through projection. Based on the graph, we developed the PrompTHis system through co-design with artists. Based on the review and analysis of the prompting history, users can better understand the impact of prompt changes and have a more effective control of image generation. A quantitative user study and qualitative interviews demonstrate that PrompTHis can help users review the prompt history, make sense of the model, and plan their creative process.