VLDB 2026 Research / reviewers in the wild / expert
Tommy Dang
dblp:98/8756 · also Dang Tuan Nhon
· DBLP profile ↗
16ranked-venue papers in the field
2as first author
3since 2021 · last 2024
0000-0001-8322-0014ORCID · verified
Domains — venue-derived; a paper can count in several
Big Data, Cloud & Distributed Data Systems · 13 (2 first)Data Mining & Knowledge Discovery · 3
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2024 | Temporal Dynamics and Anomaly Detection in Transactional NetworksabstractIn this paper, we use data visualization and visual analytics to tackle the IEEE VAST Challenge 2024 Mini Challenge 3. We use TimeArcs, measures of centrality, and multiple anomaly detection algorithms to visualize the evolution of corporate structure and identify suspicious behavior in the Oceanus Fishing Market. We then create an anomaly detection algorithm combining 3 measures of centrality and isolation forest and local outlier factor algorithms to analyze transactional networks over time and rank nodes by an anomaly score. The algorithm is tested on the VAST Challenge data as well as the 1999 DARPA Intrusion Detection Dataset. The algorithm succeeds in ranking many nodes labeled as suspicious during the VAST Challenge with high anomaly scores. It achieves a peak 97.31 percent accuracy on the DARPA dataset. This demonstrates the power of representing different types of data as transactional networks and shows the potential of this algorithm to be used as a versatile tool for other datasets. Ethan Wei, Tommy Dang |
BDCAT | 2 |
| 2022 | JobViewer: Graph-based Visualization for Monitoring High-Performance Computing SystemabstractVisualization aims to strengthen data exploration and analysis, especially for complex and high-dimensional data. High-performance computing (HPC) systems are typically large and complicated instruments that generate massive performance and operation time series. Monitoring HPC systems’ performance is a daunting task for HPC admins and researchers due to their dynamic natures. This work proposes a visual design using the bipartite graph’s idea to visualize HPC clusters’ structure, metrics, and job scheduling data. We built a web-based prototype, called JobViewer, that integrates advanced methods in visualization and human-computer interaction (HCI) to demonstrate the benefits of visualization in real-time monitoring HPC centers. We also showed real use cases and a user study to validate the efficiency and highlight the current approach’s drawbacks. Tommy Dang, Ngan V. T. Nguyen, Jie Li 0057, Alan Sill, Jon R. Hass, Yong Chen 0001 |
BDCAT | 1 |
| 2021 | RDNet: Deep Learning Model for Predicting pH H20 and pHKCl from Soil Vis-NIR SpectraabstractSoil properties are vital to profiling and utilizing soil resources. Conventional approaches to measurements of soil properties often involve costly, environmental-unfriendly, and time-consuming laboratory procedures. Conversely, machine learning (ML) and deep learning (DL) are gaining traction in giving rapid, non-destructive, and cost-saving alternatives to predictions of soil properties. These ML/DL models are convenient and fast because they utilize spectral data, such as visible and near-infrared (Vis-NIR) spectra, that can be easily collected using proximal sensors for their training and prediction purposes. However, existing ML/DL approaches to this problem pose several limitations, such as having small sample sizes, needing to divide the sample data into local areas to increase accuracy, and having relatively low accuracy. Therefore, this work experiments various ML/DL methods that leverage Vis-NIR spectra collected from a rather large number of soil samples distributed all over the world to predict $p{H_{{H_2}O}}$ and pHKCl. We then propose a DL method, called RDNet, that outperforms the other existing approaches. We also utilize visualizations to verify if the proposed model learns legitimate information from the training data. Vung Pham, David C. Weindorf, Tommy Dang |
IEEE BigData | 3 |
| 2020 | Graph Adversarial Attacks and Defense: An Empirical Study on Citation GraphabstractThis paper details the methodologies and decisions making processes used while developing the attacking and defending models for the Graph Adversarial Attacks and Defense applied to a large citation graph. To handle the large graphs, our attack strategy is twofold: 1) randomly attack the structure first, 2) keep the structure unchanged, then continue the attack on the features using the gradient-based method. On the other hand, the defender is based on 1) filtering and normalizing the feature data, 2) applying the Graph Convolutional Network model, and 3) selecting the models with the highest accuracy and robustness based on our own attacking data. We applied these strategies in KDD Cup 2020 on Graph Adversarial Attacks and Defense dataset. The attacker can drop the accuracy of a surrogate 2-layer Graph Convolutional Network model from 60% to 30% on the test set. Our defending model has 68% accuracy on the validated data and has 89% of the target labels remained the same while adding fake nodes, generated by our attacking method, to the graph. Chau Pham 0001, Vung Pham, Tommy Dang |
IEEE BigData | 3 |
| 2020 | Road Damage Detection and Classification with Detectron2 and Faster R-CNNabstractThe road is vital for many aspects of life, and road maintenance is crucial for human safety. One of the critical tasks to allow timely repair of road damages is to quickly and efficiently detect and classify them. This work details the strategies and experiments evaluated for these tasks. Specifically, we evaluate Detectron2's implementation of Faster R-CNN using different base models and configurations. We also experiment with these approaches using the Global Road Damage Detection Challenge 2020, A Track in the IEEE Big Data 2020 Big Data Cup Challenge dataset. The results show that the X101-FPN base model for Faster R-CNN with Detectron2's default configurations is efficient and general enough to be transferable to different countries in this challenge. This approach results in F1 scores of 51.0% and 51.4% for the test1 and test2 sets of the challenge, respectively. Though the visualizations show good prediction results, the F1 scores are low. Therefore, we also evaluate the prediction results against the existing annotations and discover some discrepancies. Thus, we also suggest strategies to improve the labeling process for this dataset. Vung Pham, Chau Pham 0001, Tommy Dang |
IEEE BigData | 3 |
| 2019 | MTSAD: Multivariate Time Series Abnormality Detection and VisualizationabstractDetecting outliers is one of the fundamental tasks in visual analytics and valuable in many application domains, such as suspicious network cyberattack recognition. This paper introduces an approach to analyzing and visualizing high-dimensional time series, focusing on identifying multivariate observations that are significantly different from the others. We also propose a prototype, called MTSAD, to guide users when interactively exploring abnormalities in large time series. The prototype contains two views: the main window provides an overview of identified outliers overtime, the detail window investigates and explores the ranked temporal data entries based on their outlying contributions to the overall plots. The visual interface supports a full range of interactions, such as lensing, brushing and linking, ranking, and filtering. To validate the benefits and usefulness of our approach, we demonstrate MTSAD on real-world datasets of different numbers of attributes. Vung Pham, Ngan V. T. Nguyen, Jie Li 0057, Jon R. Hass, Yong Chen 0001, Tommy Dang |
IEEE BigData | 6 |
| 2019 | Solar Flare Prediction Using Two-tier Ensemble with Deep Learning and Gradient Boosting MachineabstractThis paper describes a machine learning approach to the solar flare prediction competition, a track in IEEE Big Data 2019 Big Data Cup. The competition task is to predict whether or not there is a solar flare event basing on a given time series of solar magnetic field parameters. Our method involves exploring and constructing data-driven machine learning models for the classification task of two imbalanced class labels from time series. Specifically, the investigated models include boosting, logistic regression, multilayer perceptron neural network, and long short-term memory neural network. These models have been successfully deployed and combined in an ensemble framework with two tiers in our final proposed solution for this competition. Our proposed approach ranked at the second place in the competition (the first on the private board and the eleventh on the public board). Chau Pham 0001, Vung Pham, Tommy Dang |
IEEE BigData | 3 |
| 2019 | HackerNets: Visualizing Media Conversations on Internet of Things, Big Data, and CybersecurityabstractThe giant network of Internet of Things establishes connections between smart devices and people, with protocols to collect and share data. While the data is expanding at a fast pace in this era of Big Data, there are growing concerns about security and privacy policies. In the current Internet of Things ecosystems, at the intersection of the Internet of Things, Big Data, and Cybersecurity lies the subject that attracts the most attention. In aiding users in getting an adequate understanding, this paper introduces HackerNets, an interactive visualization for emerging topics in the crossing of IoT, Big Data, and Cybersecurity over time. To demonstrate the effectiveness and usefulness of HackerNets, we apply and evaluate the technique on the dataset from the social media platform. Hao Van, Huyen N. Nguyen, Rattikorn Hewett, Tommy Dang |
IEEE BigData | 4 |
| 2018 | HealthTvizer: Exploring Health Awareness in Twitter Data through Coordinated Multiple ViewsabstractAnalyzing public user posts and shared information on social media can assist us in measuring various population characteristics, patterns, movements, and as well as the public health conditions. In recent years, researchers have been analyzing social media (such as Facebook or Twitter feeds) to detect and predict various emerging events and market trends. Fewer attentions have been paid to the epidemic of the diseases. In this paper, we present a social media analytics tool, called HealthTvizer, for exploring health awareness using Twitter data through interactive and interconnected multiple views. We use topic modeling to pick the relevant and meaningful terms from more than 57 million tweets. We detect the disease name and related contents which are shared by the users of different geographical locations (mostly in the United States). We believe that the collected geolocations from the users' tweets can reveal the patterns of diseases for a given term which allows a researcher to detect, analyze, and explore information about the diseases and hence take necessary steps to improve public health awareness. We validate the effectiveness of HealthTvizer through an informal user study. The feedback from this study also motivates us on interesting future extensions of the tool. Tommy Dang, Ngan V. T. Nguyen, Vung Pham |
IEEE BigData | 1 |
| 2018 | FinanViz: Visualizing Emerging Topics in Financial NewsabstractThe explosion of social media has paved a way for big data in which entrepreneurs use this data to find out potential customers, market demands, individual behavior, thereby to improve existing products, to create new products according to users' need, or to analyze and evaluate financial risks. The challenges of the heterogeneity and fragmentation of data make it difficult for analysts to fully exploit the benefit of deluge information. Available statistical software lacks customization and address unknown research questions. This paper proposes FinanViz, a visual analytics tool for analyzing financial news on social media. The principal aim of FinanViz is to observe the dynamic behavior of terms/words over time along with their proximity to other terms/words. The tool provides an intuitive, interactive exploration of the financial topics and what events are emerging in which we would argue that it will give hints for financial marketers in the decision making process. Ngan V. T. Nguyen, Vinh The Nguyen 0001, Vung Pham, Tommy Dang |
IEEE BigData | 4 |
| 2018 | UFO_Tracker: Visualizing UFO sightingsabstractVisualizing and analyzing geospatial and temporal observations are common tasks for many application domains. In this paper, we introduce UFO Tracker, a visual analytic tool for analyzing unidentified flying object sightings from the National UFO Reporting Center. The goal here is to give the user a higher level view of where different types of sightings occur, to investigate whether sightings are increasing or decreasing over time, to discover the connections between different events which might happen at different geographic areas, and to quickly identify typical incidents at a given period of time without reading the whole sightings through topic modelling. Multiple visualization and data mining techniques are combined to make sense the increasingly large UFO reports which get updated hourly. The usefulness of the application is evaluated through a case study where anon-expert in ufology can find some typical interesting sightings. Our application can also be able to detect some misleading events such as missile launch or fireworks on a specific day through keywords and topic extraction. One limitation of our application is the data which is not up-todate when new sightings are posted since the application pulled and processed data locally. Our initial application targets UFO sighting reports. However, we believe our approach has wider applications in other research domains, such as analyzing text corpus obtained from social media. Vinh The Nguyen 0001, Vung Pham, Tommy Dang |
IEEE BigData | 3 |
| 2018 | CVExplorer: Multidimensional Visualization for Common Vulnerabilities and ExposuresabstractCyber attacks cause great damage to our national security, ranging from individual internet user to biggest governmental/industrial organizations, such as Equifax (Data Breach 145.5 Million Accounts, reported in July 2017) or Uber (Data Breach 57 Million Records, reported in November 2017). The cyber assault has significantly increased in breadth and depth. This paper introduces CVExplorer, a novel interactive system for visualizing cybersecurity threats reported in the National Vulnerability Database. The proposed system aims to work as a reporting and alerting tool that can help enhance the security against cyber attacks can potentially reduce network vulnerabilities. The CVExplorer system containing multiple linked views allows users to visualize the relationships of various dimensions in the large number of vulnerability reports, such as types and levels of vulnerability, vendors, and products. The CVExplorer provides an intuitive interface and supports a range of interactive features, such as filtering and ordering by vulnerability severity ratings, allowing users to narrow down topics of interest quickly. To demonstrate the effectiveness of the proposed system, we demonstrate the CVExplorer on two case studies of Common Vulnerabilities and Exposures retrieved from the National Vulnerability Database. Vung Pham, Tommy Dang |
IEEE BigData | 2 |
| 2018 | IoTViz: Visualizing emerging topics in the internet of thingsabstractThe "Internet of Things" is changing the way companies operate and consumers behave. Therefore, it is essential to capture trends in "Internet of Things". This paper proposes IoTViz, a visual analytics tool for analyzing "Internet of Things" news on social media. The principal aim of IoTViz is to observe the dynamic behavior of topics along with their proximity to other dimensions such as user comments and ratings in multiple coordinated views. IoTViz provides an interactive exploration of the IoT topics and supports of a range of interactive features, such as linking and filtering, allowing users to narrow down events of interest quickly. It is interesting to filter and visualize IoT news regarding the individual organization, e.g., user opinions/ratings regarding a company or its products. Vung Pham, Vinh The Nguyen 0001, Tommy Dang |
IEEE BigData | 3 |
| 2012 | Substantial improvements in the set-covering projection classifier CHIRP (composite hypercubes on iterated random projections)abstractIn Wilkinson et al. [2011] we introduced a new set-covering random projection classifier that achieved average error lower than that of other classifiers in the Weka platform. This classifier was based on an L ∞ norm distance function and exploited an iterative sequence of three stages (projecting, binning, and covering) to deal with the curse of dimensionality, computational complexity, and nonlinear separability. We now present substantial changes that improve robustness and reduce training and testing time by almost an order of magnitude without jeopardizing CHIRP's outstanding error performance. Leland Wilkinson, Anushka Anand, Tommy Dang |
ACM Trans. Knowl. Discov. Data | 3 |
| 2011 | CHIRP: a new classifier based on composite hypercubes on iterated random projectionsabstractWe introduce a classifier based on the L-infinity norm. This classifier, called CHIRP, is an iterative sequence of three stages (projecting, binning, and covering) that are designed to deal with the curse of dimensionality, computational complexity, and nonlinear separability. CHIRP is not a hybrid or modification of existing classifiers; it employs a new covering algorithm. The accuracy of CHIRP on widely-used benchmark datasets exceeds the accuracy of competitors. Its computational complexity is sub-linear in number of instances and number of variables and subquadratic in number of classes. Leland Wilkinson, Anushka Anand, Tommy Dang |
KDD | 3 |
| 2009 | An L-infinity Norm Visual ClassifierabstractWe introduce a mathematical framework, based on the L∞norm distance metric, to describe human interactions in a visual data mining environment. We use the framework to build a classifier that involves an algebra on hyper-rectangles. Our classifier, called VisClassifier, generates set-wise rules from simple gestures in an exploratory visual GUI. Logging these rules allows us to apply our analysis to a new sample or batch of data so that we can assess the predictive power of our visual-processing motivated classifier. The accuracy of this classifier on widely-used benchmark datasets rivals the accuracy of competitive classifiers. Anushka Anand, Leland Wilkinson, Tommy Dang |
ICDM | 3 |