Sang-Chul Lee

Dr. Sang-Chul Lee

Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

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

Representative Publications

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13 April 2022 in Applied Sciences
Verified
Journal Article
Open access
PDF file
SLSuk-Young Lim
Suk-Young Lim
DCDong-Kyu Chae
Dong-Kyu Chae
SLSang-Chul Lee
Sang-Chul Lee
Fake media, generated by methods such as deepfakes, have become indistinguishable from real media, but their detection has not improved at the same pace. Furthermore, the absence of interpretability on deepfake detection models makes their reliability questionable. In this paper, we present a human perception level of interpretability for deepfake audio detection. Based on their characteristics, we implement several explainable artificial intelligence (XAI) methods used for image classification on an audio-related task. In addition, by examining the human cognitive process of XAI on image classification, we suggest the use of a corresponding data format for providing interpretability. Using this novel concept, a fresh interpretation using attribution scores can be provided.

18 October 2007 in International Journal of Urology
Verified
Journal Article
Closed access
PDF file
YKYong-June Kim
Yong-June Kim
BHByung Kuy Han
Byung Kuy Han
SHSung Kyu Hong
Sung Kyu Hong
SBSeok‐Soo Byun
Seok‐Soo Byun
WKWun‐Jae Kim
Wun‐Jae Kim
SLSang-Chul Lee
Sang-Chul Lee

1 April 2022 in Electronics
Verified
Journal Article
Open access
PDF file
JLJongsoo Lee
Jongsoo Lee
JSJung Ah Shin
Jung Ah Shin
DCDong-Kyu Chae
Dong-Kyu Chae
SLSang-Chul Lee
Sang-Chul Lee
The goal of a tour recommendation is to recommend the best destinations according to the preferences of each tourist. The task of tour recommendation is challenging in that it not only has to consider the ratings, as do existing traditional recommendation problems, but it must also consider the personalization of the unique characteristics, such as diversity, travel distance, and popularity of the travel destination, which previous studies have failed to take into account. In this paper, we propose, for the first time, aspect personalization: we find out how important each user considers the diversity, distance and popularity of a travel destination when choosing where to visit. Then, we provide recommendations on tourist attractions by combining the personalized score for each factor and the predicted score. For the evaluation, we gathered user ratings and metadata of POIs from TripAdvisor and Naver. Experimental results showed that the proposed method had an 82%, 24% and 20% improvement in precision and a 129%, 35% and 22% improvement in recall in terms of top-1, top-2 and top-3 recommendations.

5 June 2024 in Future Generation Computer Systems
Verified
Journal Article
Closed access
XZXueyi Zhou
Xueyi Zhou
DCDong-Kyu Chae
Dong-Kyu Chae
SLSang-Chul Lee
Sang-Chul Lee

15 October 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
IKInhwa Koo
Inhwa Koo
DCDong-Kyu Chae
Dong-Kyu Chae
SLSang-Chul Lee
Sang-Chul Lee
Despite the impressive performance of deep neural networks on many different vision tasks, they have been known to be vulnerable to intentionally added noise to input images. To combat these adversarial examples (AEs), improving the adversarial robustness of models has emerged as an important research topic, and research has been conducted in various directions including adversarial training, image denoising, and adversarial purification. Among them, this paper focuses on adversarial purification, which is a kind of pre-processing that removes noise before AEs enter a classification model. The advantage of adversarial purification is that it can improve robustness without affecting the model’s nature, while another defense techniques like adversarial training suffer from a decrease in model accuracy. Our proposed purification framework utilizes a Convolutional Autoencoder as a base model to capture the features of images and their spatial structure.We further aim to improve the adversarial robustness of our purification model by distilling the knowledge from teacher models. To this end, we train two Convolutional Autoencoders (teachers), one with adversarial training and the other with normal training. Then, through ensemble knowledge distillation, we transfer the ability of denoising and restoring of original images to the student model (purification model). Our extensive experiments confirm that our student model achieves high purification performance(i.e., how accurately a pre-trained classification model classifies purified images). The ablation study confirms the positive effect of our idea of ensemble knowledge distillation from two teachers on performance.

26 September 2023 in Preprints.org
Verified
Preprint
Open access
PDF file
IKInhwa Koo
Inhwa Koo
DCDong-Kyu Chae
Dong-Kyu Chae
SLSang-Chul Lee
Sang-Chul Lee
Despite the impressive performance of deep neural networks on many different vision tasks, they have been known to be vulnerable to intentionally added noise to input images. To combat these adversarial examples (AEs), improving the adversarial robustness of models has emerged as an important research topic, and research has been conducted in various directions including adversarial training, image denoising, and adversarial purification. Among them, this paper focuses on adversarial purification, which is a kind of pre-processing that removes noise before AEs enter a classification model. The advantage of adversarial purification is that it can improve robustness without affecting the model’s nature, while another defense techniques like adversarial training suffer from a decrease in model accuracy. Our proposed purification framework utilizes a Convolutional Autoencoder as a base model to capture the features of images and their spatial structure. We further aim to improve the adversarial robustness of our purification model by distilling the knowledge from teacher models. To this end, we train two Convolutional Autoencoders (teachers), one with adversarial training and the other with normal training. Then, through ensemble knowledge distillation, we transfer the ability of denoising and restoring of original images to the student model (purification model). Our extensive experiments confirm that our student model achieves high purification performance(i.e., how accurately a pre-trained classification model classifies purified images). The ablation study confirms the positive effect of our idea of ensemble knowledge distillation from two teachers on performance.