1:A Visual Analytics System for Multi-model Comparison on Clinical Data Predictions [PDF] [YouKu] [Vimeo]

Yiran Li University of California, Davis
Takanori Fujiwara University of California, Davis
Yong K. Choi University of California, Davis
Katherine K. Kim University of California, Davis
Kwan-Liu Ma University of California, Davis

Abstract: There is a growing trend of applying machine learning methods to medical datasets in order to predict patients’ future status. Although some of these methods achieve high performance, challenges still exist in comparing and evaluating different models through their interpretable information. Such analytics can help clinicians improve evidence-based medical decision making. In this work, we develop a visual analytics system that compares multiple models’ prediction criteria and evaluates their consistency. With our system, users can generate knowledge on different models’ inner criteria and how confidently we can rely on each model’s prediction for a certain patient. Through a case study of a publicly available clinical dataset, we demonstrate the effectiveness of our visual analytics system to assist clinicians and researchers in comparing and quantitatively evaluating different machine learning methods.

2: CECAV: Collective Ensemble Comparison and Visualization using Deep Neural Networks [PDF] [YouKu] [Vimeo]

Wenbin He The Ohio State University
Junpeng Wang Visa Research
Hanqi Guo Argonne National Laboratory
Han-Wei Shen The Ohio State University
Tom Peterka Argonne National Laboratory

Abstract: We propose a deep learning approach to collectively compare two or multiple ensembles, each of which is a collection of simulation outputs. The purpose of collective comparison is to help scientists understand differences between simulation models by comparing their ensemble simulation outputs. However, the collective comparison is non-trivial because the spatiotemporal distributions of ensemble simulation outputs reside in a very high dimensional space. To this end, we choose to train a deep discriminative neural network to measure the dissimilarity between two given ensembles, and to identify when and where the two ensembles are different. We also design and develop a visualization system to help users understand the collective comparison results based on the discriminative network. We demonstrate the effectiveness of our approach with two real-world applications, including the ensemble comparison of the community atmosphere model (CAM) and the rapid radiative transfer model for general circulation models (RRTMG) for climate research, and the comparison of computational fluid dynamics (CFD) ensembles with different spatial resolutions.

3: Toward automatic comparison of visualization techniques: Application to graph visualization [PDF] [YouKu] [Vimeo]

L. Giovannangeli University of Bordeaux
R. Bourqui University of Bordeaux
R. Giot University of Bordeaux
D. Auber University of Bordeaux

Abstract: Many end-user evaluations of data visualization techniques have been run during the last decades. Their results are cornerstones to build efficient visualization systems. However, designing such an evaluation is always complex and time-consuming and may end in a lack of statistical evidence and reproducibility. We believe that modern and efficient computer vision techniques, such as deep convolutional neural networks (CNNs), may help visualization researchers to build and/or adjust their evaluation hypothesis. The basis of our idea is to train machine learning models on several visualization techniques to solve a specific task. Our assumption is that it is possible to compare the efficiency of visualization techniques based on the performance of their corresponding model. As current machine learning models are not able to strictly reflect human capabilities, including their imperfections, such results should be interpreted with caution. However, we think that using machine learning-based pre-evaluation, as a pre-process of standard user evaluations, should help researchers to perform a more exhaustive study of their design space. Thus, it should improve their final user evaluation by providing it better test cases. In this paper, we present the results of two experiments we have conducted to assess how correlated the performance of users and computer vision techniques can be. That study compares two mainstream graph visualization techniques: node-link (NL) and adjacency-matrix (AM) diagrams. Using two well-known deep convolutional neural networks, we partially reproduced user evaluations from Ghoniem et al. and from Okoe et al.. These experiments showed that some user evaluation results can be reproduced automatically.

4: Visual exploration of latent space for traditional Chinese music [PDF] [YouKu] [Vimeo]

Jingyi Shen The Ohio State University
Runqi Wang The Ohio State University
Han-Wei Shen The Ohio State University

Abstract: Generating compact and effective numerical representations of data is a fundamental step for many machine learning tasks. Traditionally, handcrafted features are used but as deep learning starts to show its potential, using deep learning models to extract compact representations becomes a new trend. Among them, adopting vectors from the model’s latent space is the most popular. There are several studies focused on visual analysis of latent space in NLP and computer vision. However, relatively little work has been done for music information retrieval (MIR) especially incorporating visualization. To bridge this gap, we propose a visual analysis system utilizing Autoencoders to facilitate analysis and exploration of traditional Chinese music. Due to the lack of proper traditional Chinese music data, we construct a labeled dataset from a collection of pre-recorded audios and then convert them into spectrograms. Our system takes music features learned from two deep learning models (a fully-connected Autoencoder and a Long Short-Term Memory (LSTM) Autoencoder) as input. Through interactive selection, similarity calculation, clustering and listening, we show that the latent representations of the encoded data allow our system to identify essential music elements, which lay the foundation for further analysis and retrieval of Chinese music in the future.

5: Comparative visual analytics for assessing medical records with sequence embedding [PDF] [YouKu] [Vimeo]

Rongchen Guo Beihang University
Takanori Fujiwara University of California, Davis
Yiran Li University of California, Davis
Kelly M. Lima University of California, Davis
Soman Sen University of California, Davis
Nam K. Tran University of California, Davis
Kwan-Liu Ma e, University of California, Davis

Abstract: Machine learning for data-driven diagnosis has been actively studied in medicine to provide better healthcare. Supporting analysis of a patient cohort similar to a patient under treatment is a key task for clinicians to make decisions with high confidence. However, such analysis is not straightforward due to the characteristics of medical records: high dimensionality, irregularity in time, and sparsity. To address this challenge, we introduce a method for similarity calculation of medical records. Our method employs event and sequence embeddings. While we use an autoencoder for the event embedding, we apply its variant with the self-attention mechanism for the sequence embedding. Moreover, in order to better handle the irregularity of data, we enhance the self-attention mechanism with consideration of different time intervals. We have developed a visual analytics system to support comparative studies of patient records. To make a comparison of sequences with different lengths easier, our system incorporates a sequence alignment method. Through its interactive interface, the user can quickly identify patients of interest and conveniently review both the temporal and multivariate aspects of the patient records. We demonstrate the effectiveness of our design and system with case studies using a real-world dataset from the neonatal intensive care unit of UC Davis.

6: Token-wise sentiment decomposition for ConvNet: Visualizing a sentiment classifier [PDF] [YouKu] [Vimeo]

Piyush Chawla The Ohio State University
Subhashis Hazarika The Ohio State University
Han-Wei Shen The Ohio State University

Abstract: Convolutional neural networks are one of the most important and widely used constructs in natural language processing and AI in general. In many applications, they have achieved state-of-the-art performance, with training time faster than the other alternatives. However, due to their limited interpretability, they are less favored by practitioners over attention-based models, like RNNs and self-attention (Transformers), which can be visualized and interpreted more intuitively by analyzing the attention-weight heat-maps. In this work, we present a visualization technique that can be used to understand the inner workings of text-based CNN models. We also show how this method can be used to generate adversarial examples and learn the shortcomings of the training data.