Interpretable Prototype-based Graph Information Bottleneck

The success of Graph Neural Networks (GNNs) has led to a need for understanding their decision-making process and providing explanations for their predictions, which has given rise to explainable AI (XAI) that offers transparent explanations for black-box models. Recently, the use of prototypes has successfully improved the explainability of models by learning prototypes to imply training graphs that affect the prediction. However, these approaches tend to provide prototypes with excessive information from the entire graph, leading to the exclusion of key substructures or the inclusion of irrelevant substructures, which can limit both the interpretability and the performance of the model in downstream tasks. In this work, we propose a novel framework of explainable GNNs, called interpretable Prototype-based Graph Information Bottleneck (PGIB) that incorporates prototype learning within the information bottleneck framework to provide prototypes with the key subgraph from the input graph that is important for the model prediction. This is the first work that incorporates prototype learning into the process of identifying the key subgraphs that have a critical impact on the prediction performance. Extensive experiments, including qualitative analysis, demonstrate that PGIB outperforms state-of-the-art methods in terms of both prediction performance and explainability.Comment: NeurIPS 202

Lightweight and Robust Representation of Economic Scales from Satellite Imagery

Satellite imagery has long been an attractive data source that provides a wealth of information on human-inhabited areas. While super resolution satellite images are rapidly becoming available, little study has focused on how to extract meaningful information about human habitation patterns and economic scales from such data. We present READ, a new approach for obtaining essential spatial representation for any given district from high-resolution satellite imagery based on deep neural networks. Our method combines transfer learning and embedded statistics to efficiently learn critical spatial characteristics of arbitrary size areas and represent them into a fixed-length vector with minimal information loss. Even with a small set of labels, READ can distinguish subtle differences between rural and urban areas and infer the degree of urbanization. An extensive evaluation demonstrates the model outperforms the state-of-the-art in predicting economic scales, such as population density for South Korea (R^2=0.9617), and shows a high potential use for developing countries where district-level economic scales are not known.Comment: Accepted for oral presentation at AAAI 202

Towards Attack-tolerant Federated Learning via Critical Parameter Analysis

Federated learning is used to train a shared model in a decentralized way without clients sharing private data with each other. Federated learning systems are susceptible to poisoning attacks when malicious clients send false updates to the central server. Existing defense strategies are ineffective under non-IID data settings. This paper proposes a new defense strategy, FedCPA (Federated learning with Critical Parameter Analysis). Our attack-tolerant aggregation method is based on the observation that benign local models have similar sets of top-k and bottom-k critical parameters, whereas poisoned local models do not. Experiments with different attack scenarios on multiple datasets demonstrate that our model outperforms existing defense strategies in defending against poisoning attacks.Comment: ICCV'23 Accepte

FedX: Unsupervised Federated Learning with Cross Knowledge Distillation

This paper presents FedX, an unsupervised federated learning framework. Our model learns unbiased representation from decentralized and heterogeneous local data. It employs a two-sided knowledge distillation with contrastive learning as a core component, allowing the federated system to function without requiring clients to share any data features. Furthermore, its adaptable architecture can be used as an add-on module for existing unsupervised algorithms in federated settings. Experiments show that our model improves performance significantly (1.58--5.52pp) on five unsupervised algorithms.Comment: Accepted and will be published at ECCV202

FedDefender: Client-Side Attack-Tolerant Federated Learning

Federated learning enables learning from decentralized data sources without compromising privacy, which makes it a crucial technique. However, it is vulnerable to model poisoning attacks, where malicious clients interfere with the training process. Previous defense mechanisms have focused on the server-side by using careful model aggregation, but this may not be effective when the data is not identically distributed or when attackers can access the information of benign clients. In this paper, we propose a new defense mechanism that focuses on the client-side, called FedDefender, to help benign clients train robust local models and avoid the adverse impact of malicious model updates from attackers, even when a server-side defense cannot identify or remove adversaries. Our method consists of two main components: (1) attack-tolerant local meta update and (2) attack-tolerant global knowledge distillation. These components are used to find noise-resilient model parameters while accurately extracting knowledge from a potentially corrupted global model. Our client-side defense strategy has a flexible structure and can work in conjunction with any existing server-side strategies. Evaluations of real-world scenarios across multiple datasets show that the proposed method enhances the robustness of federated learning against model poisoning attacks.Comment: KDD'23 research track accepte

Design of Automation Environment for Analyzing Various IoT Malware

With the increasing proliferation of IoT systems, the security of IoT systems has become very important to individuals and businesses. IoT malware has been increasing exponentially since the emergence of Mirai in 2016. Because the IoT system environment is diverse, IoT malware also has various environments. In the case of existing analysis systems, there is no environment for dynamic analysis by running IoT malware of various architectures. It is inefficient in terms of time and cost to build an environment that analyzes malware one by one for analysis. The purpose of this paper is to improve the problems and limitations of the existing analysis system and provide an environment to analyze a large amount of IoT malware. Using existing open source analysis tools suitable for various IoT malicious codes and QEMU, a virtualization software, the environment in which the actual malicious code will run is built, and the library or system call that is actually called is statically and dynamically analyzed. In the text, the analysis system is applied to the actual collected malicious code to check whether it is analyzed and derive statistics. Information on the architecture of malicious code, attack method, command used, and access path can be checked, and this information can be used as a basis for malicious code detection research or classification research. The advantages are described of the system designed compared to the most commonly used automated analysis tools and improvements to existing limitations

Bobsleigh start interval times and three-dimensional motion analysis of the lower limb joints in preparation for the 2018 Pyeongchang Winter Olympics

This study aimed to provide data to improve the technique of Korean bobsledders. To this end, we measured the start interval times of bobsledders with different performance levels and performed a motion analysis of the lower limb joints during the start interval. We divided 12 Korean bobsledders into a superior group and an inferior group before measuring the interval times and performing the motion analysis of the lower limb joints at the start of the bobsleigh. The start interval times showed a statistically significant difference between the superior and inferior groups (p \u3c .05). The motion analysis of the lower limb joints revealed significant differences in hip flexion and extension, and in ankle dorsiflexion, plantar flexion, and supination (p \u3c .05). Based on these differences, we deduced that the superior bobsledders achieved superior start times by using movements that focus more on horizontal changes in the center of gravity than on vertical changes, and movements that facilitate a longer stride