DevLan/vispubs huggingface dataset:
Shape Grammar Extraction for Efficient Query-by-Sketch Pattern Matching in Long Time Series
Authors: Prithiviraj K. Muthumanickam, Katerina Vrotsou, Matthew Cooper 0001, Jimmy Johansson 0001
Published at VAST, 2016

Long time-series, involving thousands or even millions of time steps, are common in many application domains but remain very difficult to explore interactively. Often the analytical task in such data is to identify specific patterns, but this is a very complex and computationally difficult problem and so focusing the search in order to only identify interesting patterns is a common solution. We propose an efficient method for exploring user-sketched patterns, incorporating the domain expert's knowledge, in time series data through a shape grammar based approach. The shape grammar is extracted from the time series by considering the data as a combination of basic elementary shapes positioned across different amplitudes. We represent these basic shapes using a ratio value, perform binning on ratio values and apply a symbolic approximation. Our proposed method for pattern matching is amplitude-, scale- and translation-invariant and, since the pattern search and pattern constraint relaxation happen at the symbolic level, is very efficient permitting its use in a real-time/online system. We demonstrate the effectiveness of our method in a case study on stock market data although it is applicable to any numeric time series data.
SmartAdP: Visual Analytics of Large-scale Taxi Trajectories for Selecting Billboard Locations
Authors: Dongyu Liu, Di Weng, Yuhong Li, Jie Bao 0003, Yu Zheng 0004, Huamin Qu, Yingcai Wu
Published at VAST, 2016

The problem of formulating solutions immediately and comparing them rapidly for billboard placements has plagued advertising planners for a long time, owing to the lack of efficient tools for in-depth analyses to make informed decisions. In this study, we attempt to employ visual analytics that combines the state-of-the-art mining and visualization techniques to tackle this problem using large-scale GPS trajectory data. In particular, we present SmartAdP, an interactive visual analytics system that deals with the two major challenges including finding good solutions in a huge solution space and comparing the solutions in a visual and intuitive manner. An interactive framework that integrates a novel visualization-driven data mining model enables advertising planners to effectively and efficiently formulate good candidate solutions. In addition, we propose a set of coupled visualizations: a solution view with metaphor-based glyphs to visualize the correlation between different solutions; a location view to display billboard locations in a compact manner; and a ranking view to present multi-typed rankings of the solutions. This system has been demonstrated using case studies with a real-world dataset and domain-expert interviews. Our approach can be adapted for other location selection problems such as selecting locations of retail stores or restaurants using trajectory data.
SocialBrands: Visual analysis of public perceptions of brands on social media
Authors: Xiaotong Liu, Anbang Xu, Liang Gou, Haibin Liu, Rama Akkiraju, Han-Wei Shen
Published at VAST, 2016

Public perceptions of a brand is critical to its performance. While social media has demonstrated a huge potential to shape public perceptions of brands, existing tools are not intuitive and explanatory for domain users to use as they fail to provide a comprehensive analysis framework for perceptions of brands. In this paper, we present SocialBrands, a novel visual analysis tool for brand managers to understand public perceptions of brands on social media. Social-Brands leverages brand personality framework in marketing literature and social computing approaches to compute the personality of brands from three driving factors (user imagery, employee imagery, and official announcement) on social media, and construct an evidence network explaining the association between brand personality and driving factors. These computational results are then integrated with new interactive visualizations to help brand managers understand personality traits and their driving factors. We demonstrate the usefulness and effectiveness of SocialBrands through a series of user studies with brand managers in an enterprise context. Design lessons are also derived from our studies.
Squares: Supporting Interactive Performance Analysis for Multiclass Classifiers
Authors: Donghao Ren, Saleema Amershi, Bongshin Lee, Jina Suh, Jason D. Williams
Published at VAST, 2016

Performance analysis is critical in applied machine learning because it influences the models practitioners produce. Current performance analysis tools suffer from issues including obscuring important characteristics of model behavior and dissociating performance from data. In this work, we present Squares, a performance visualization for multiclass classification problems. Squares supports estimating common performance metrics while displaying instance-level distribution information necessary for helping practitioners prioritize efforts and access data. Our controlled study shows that practitioners can assess performance significantly faster and more accurately with Squares than a confusion matrix, a common performance analysis tool in machine learning.
Supporting visual exploration for multiple users in large display environments
Authors: Sriram Karthik Badam, Fereshteh Amini, Niklas Elmqvist, Pourang Irani
Published at VAST, 2016

We present a design space exploration of interaction techniques for supporting multiple collaborators exploring data on a shared large display. Our proposed solution is based on users controlling individual lenses using both explicit gestures as well as proxemics: the spatial relations between people and physical artifacts such as their distance, orientation, and movement. We discuss different design considerations for implicit and explicit interactions through the lens, and evaluate the user experience to find a balance between the implicit and explicit interaction styles. Our findings indicate that users favor implicit interaction through proxemics for navigation and collaboration, but prefer using explicit mid-air gestures to perform actions that are perceived to be direct, such as terminating a lens composition. Based on these results, we propose a hybrid technique utilizing both proxemics and mid-air gestures, along with examples applying this technique to other datasets. Finally, we performed a usability evaluation of the hybrid technique and observed user performance improvements in the presence of both implicit and explicit interaction styles.
TextTile: An Interactive Visualization Tool for Seamless Exploratory Analysis of Structured Data and Unstructured Text
Authors: Cristian Felix, Anshul Vikram Pandey, Enrico Bertini
Published at VAST, 2016

We describe TextTile, a data visualization tool for investigation of datasets and questions that require seamless and flexible analysis of structured data and unstructured text. TextTile is based on real-world data analysis problems gathered through our interaction with a number of domain experts and provides a general purpose solution to such problems. The system integrates a set of operations that can interchangeably be applied to the structured as well as to unstructured text part of the data to generate useful data summaries. Such summaries are then organized in visual tiles in a grid layout to allow their analysis and comparison. We validate TextTile with task analysis, use cases and a user study showing the system can be easily learned and proficiently used to carry out nontrivial tasks.
The DataSpace for HIV vaccine studies
Authors: David McColgin, Paul Hoover, Mark Igra
Published at VAST, 2016

The DataSpace for HIV vaccine studies is a discovery tool available on the web to hundreds of investigators. We designed it to help them better understand activity in the field and explore new ideas latent in completed research. The DataSpace harmonizes immunoassay results and study metadata so that a broader research community can pursue more flexible discovery than the typical centrally planned analyses. Insights from human-centered design and beta evaluation suggest strong potential for visual analytics that may also apply to other efforts in open science. The contribution of this paper is to elucidate key domain challenges and demonstrate an application that addresses them. We made several changes to familiar visualizations to support key tasks such as identifying and filtering to a cohort of interest, making meaningful comparisons of time series data from multiple studies that have different plans, and preserving analytic context when making data transformations and comparisons that would normally exclude some data.
The semantics of sketch: Flexibility in visual query systems for time series data
Authors: Michael Correll, Michael Gleicher
Published at VAST, 2016

Sketching allows analysts to specify complex and free-form patterns of interest. Visual query systems can make use of sketches to locate these patterns of interest in large datasets. However, sketching is ambiguous: the same drawing could represent a multitude of potential queries. In this work, we investigate these ambiguities as they apply to visual query systems for time series data. We define a class of “invariants” - the properties of a time series that the analyst wishes to ignore when performing a sketch-based query. We present the results of a crowd-sourced study, showing that these invariants are key components of how people rate the strength of match between sketch and target. We adapt a number of algorithms for time series matching to support invariants in sketches. Lastly, we present a web-deployed prototype sketch-based visual query system that relies on these invariants. We apply the prototype to data from finance, the digital humanities, and political science.
TopicLens: Efficient Multi-Level Visual Topic Exploration of Large-Scale Document Collections
Authors: Minjeong Kim, Kyeongpil Kang, Deok Gun Park 0001, Jaegul Choo, Niklas Elmqvist
Published at VAST, 2016

Topic modeling, which reveals underlying topics of a document corpus, has been actively adopted in visual analytics for large-scale document collections. However, due to its significant processing time and non-interactive nature, topic modeling has so far not been tightly integrated into a visual analytics workflow. Instead, most such systems are limited to utilizing a fixed, initial set of topics. Motivated by this gap in the literature, we propose a novel interaction technique called TopicLens that allows a user to dynamically explore data through a lens interface where topic modeling and the corresponding 2D embedding are efficiently computed on the fly. To support this interaction in real time while maintaining view consistency, we propose a novel efficient topic modeling method and a semi-supervised 2D embedding algorithm. Our work is based on improving state-of-the-art methods such as nonnegative matrix factorization and t-distributed stochastic neighbor embedding. Furthermore, we have built a web-based visual analytics system integrated with TopicLens. We use this system to measure the performance and the visualization quality of our proposed methods. We provide several scenarios showcasing the capability of TopicLens using real-world datasets.
Toward Theoretical Techniques for Measuring the Use of Human Effort in Visual Analytic Systems
Authors: R. Jordan Crouser, Lyndsey Franklin, Alex Endert, Kristin A. Cook
Published at VAST, 2016

Visual analytic systems have long relied on user studies and standard datasets to demonstrate advances to the state of the art, as well as to illustrate the efficiency of solutions to domain-specific challenges. This approach has enabled some important comparisons between systems, but unfortunately the narrow scope required to facilitate these comparisons has prevented many of these lessons from being generalized to new areas. At the same time, advanced visual analytic systems have made increasing use of human-machine collaboration to solve problems not tractable by machine computation alone. To continue to make progress in modeling user tasks in these hybrid visual analytic systems, we must strive to gain insight into what makes certain tasks more complex than others. This will require the development of mechanisms for describing the balance to be struck between machine and human strengths with respect to analytical tasks and workload. In this paper, we argue for the necessity of theoretical tools for reasoning about such balance in visual analytic systems and demonstrate the utility of the Human Oracle Model for this purpose in the context of sensemaking in visual analytics. Additionally, we make use of the Human Oracle Model to guide the development of a new system through a case study in the domain of cybersecurity.
Towards Better Analysis of Deep Convolutional Neural Networks
Authors: Mengchen Liu, Jiaxin Shi, Zhen Li 0044, Chongxuan Li, Jun Zhu 0001, Shixia Liu
Published at VAST, 2016

Deep convolutional neural networks (CNNs) have achieved breakthrough performance in many pattern recognition tasks such as image classification. However, the development of high-quality deep models typically relies on a substantial amount of trial-and-error, as there is still no clear understanding of when and why a deep model works. In this paper, we present a visual analytics approach for better understanding, diagnosing, and refining deep CNNs. We formulate a deep CNN as a directed acyclic graph. Based on this formulation, a hybrid visualization is developed to disclose the multiple facets of each neuron and the interactions between them. In particular, we introduce a hierarchical rectangle packing algorithm and a matrix reordering algorithm to show the derived features of a neuron cluster. We also propose a biclustering-based edge bundling method to reduce visual clutter caused by a large number of connections between neurons. We evaluated our method on a set of CNNs and the results are generally favorable.
ViDX: Visual Diagnostics of Assembly Line Performance in Smart Factories
Authors: Panpan Xu, Honghui Mei, Ren Liu, Wei Chen 0001
Published at VAST, 2016

Visual analytics plays a key role in the era of connected industry (or industry 4.0, industrial internet) as modern machines and assembly lines generate large amounts of data and effective visual exploration techniques are needed for troubleshooting, process optimization, and decision making. However, developing effective visual analytics solutions for this application domain is a challenging task due to the sheer volume and the complexity of the data collected in the manufacturing processes. We report the design and implementation of a comprehensive visual analytics system, ViDX. It supports both real-time tracking of assembly line performance and historical data exploration to identify inefficiencies, locate anomalies, and form hypotheses about their causes and effects. The system is designed based on a set of requirements gathered through discussions with the managers and operators from manufacturing sites. It features interlinked views displaying data at different levels of detail. In particular, we apply and extend the Marey's graph by introducing a time-aware outlier-preserving visual aggregation technique to support effective troubleshooting in manufacturing processes. We also introduce two novel interaction techniques, namely the quantiles brush and samples brush, for the users to interactively steer the outlier detection algorithms. We evaluate the system with example use cases and an in-depth user interview, both conducted together with the managers and operators from manufacturing plants. The result demonstrates its effectiveness and reports a successful pilot application of visual analytics for manufacturing in smart factories.
VisFlow - Web-based Visualization Framework for Tabular Data with a Subset Flow Model
Authors: Bowen Yu 0004, Cláudio T. Silva
Published at VAST, 2016

Data flow systems allow the user to design a flow diagram that specifies the relations between system components which process, filter or visually present the data. Visualization systems may benefit from user-defined data flows as an analysis typically consists of rendering multiple plots on demand and performing different types of interactive queries across coordinated views. In this paper, we propose VisFlow, a web-based visualization framework for tabular data that employs a specific type of data flow model called the subset flow model. VisFlow focuses on interactive queries within the data flow, overcoming the limitation of interactivity from past computational data flow systems. In particular, VisFlow applies embedded visualizations and supports interactive selections, brushing and linking within a visualization-oriented data flow. The model requires all data transmitted by the flow to be a data item subset (i.e. groups of table rows) of some original input table, so that rendering properties can be assigned to the subset unambiguously for tracking and comparison. VisFlow features the analysis flexibility of a flow diagram, and at the same time reduces the diagram complexity and improves usability. We demonstrate the capability of VisFlow on two case studies with domain experts on real-world datasets showing that VisFlow is capable of accomplishing a considerable set of visualization and analysis tasks. The VisFlow system is available as open source on GitHub.
VisMatchmaker: Cooperation of the User and the Computer in Centralized Matching Adjustment
Authors: Po-Ming Law, Wenchao Wu, Yixian Zheng, Huamin Qu
Published at VAST, 2016

Centralized matching is a ubiquitous resource allocation problem. In a centralized matching problem, each agent has a preference list ranking the other agents and a central planner is responsible for matching the agents manually or with an algorithm. While algorithms can find a matching which optimizes some performance metrics, they are used as a black box and preclude the central planner from applying his domain knowledge to find a matching which aligns better with the user tasks. Furthermore, the existing matching visualization techniques (i.e. bipartite graph and adjacency matrix) fail in helping the central planner understand the differences between matchings. In this paper, we present VisMatchmaker, a visualization system which allows the central planner to explore alternatives to an algorithm-generated matching. We identified three common tasks in the process of matching adjustment: problem detection, matching recommendation and matching evaluation. We classified matching comparison into three levels and designed visualization techniques for them, including the number line view and the stacked graph view. Two types of algorithmic support, namely direct assignment and range search, and their interactive operations are also provided to enable the user to apply his domain knowledge in matching adjustment.
Visual analysis and coding of data-rich user behavior
Authors: Tanja Blascheck, Fabian Beck 0001, Sebastian Baltes, Thomas Ertl, Daniel Weiskopf
Published at VAST, 2016

Investigating user behavior involves abstracting low-level events to higher-level concepts. This requires an analyst to study individual user activities, assign codes which categorize behavior, and develop a consistent classification scheme. To better support this reasoning process of an analyst, we suggest a novel visual analytics approach which integrates rich user data including transcripts, videos, eye movement data, and interaction logs. Word-sized visualizations embedded into a tabular representation provide a space-efficient and detailed overview of user activities. An analyst assigns codes, grouped into code categories, as part of an interactive process. Filtering and searching helps to select specific activities and focus an analysis. A comparison visualization summarizes results of coding and reveals relationships between codes. Editing features support efficient assignment, refinement, and aggregation of codes. We demonstrate the practical applicability and usefulness of our approach in a case study and describe expert feedback.
Visual Analysis of MOOC Forums with iForum
Authors: Siwei Fu, Jian Zhao 0010, Weiwei Cui, Huamin Qu
Published at VAST, 2016

Discussion forums of Massive Open Online Courses (MOOC) provide great opportunities for students to interact with instructional staff as well as other students. Exploration of MOOC forum data can offer valuable insights for these staff to enhance the course and prepare the next release. However, it is challenging due to the large, complicated, and heterogeneous nature of relevant datasets, which contain multiple dynamically interacting objects such as users, posts, and threads, each one including multiple attributes. In this paper, we present a design study for developing an interactive visual analytics system, called iForum, that allows for effectively discovering and understanding temporal patterns in MOOC forums. The design study was conducted with three domain experts in an iterative manner over one year, including a MOOC instructor and two official teaching assistants. iForum offers a set of novel visualization designs for presenting the three interleaving aspects of MOOC forums (i.e., posts, users, and threads) at three different scales. To demonstrate the effectiveness and usefulness of iForum, we describe a case study involving field experts, in which they use iForum to investigate real MOOC forum data for a course on JAVA programming.
Visual Analytics for Mobile Eye Tracking
Authors: Kuno Kurzhals, Marcel Hlawatsch, Christof Seeger, Daniel Weiskopf
Published at VAST, 2016

The analysis of eye tracking data often requires the annotation of areas of interest (AOIs) to derive semantic interpretations of human viewing behavior during experiments. This annotation is typically the most time-consuming step of the analysis process. Especially for data from wearable eye tracking glasses, every independently recorded video has to be annotated individually and corresponding AOIs between videos have to be identified. We provide a novel visual analytics approach to ease this annotation process by image-based, automatic clustering of eye tracking data integrated in an interactive labeling and analysis system. The annotation and analysis are tightly coupled by multiple linked views that allow for a direct interpretation of the labeled data in the context of the recorded video stimuli. The components of our analytics environment were developed with a user-centered design approach in close cooperation with an eye tracking expert. We demonstrate our approach with eye tracking data from a real experiment and compare it to an analysis of the data by manual annotation of dynamic AOIs. Furthermore, we conducted an expert user study with 6 external eye tracking researchers to collect feedback and identify analysis strategies they used while working with our application.