Yongwha Chung

Prof. Yongwha Chung

Department of Computer Convergence Software, Korea University, Sejong City 30019, Korea

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

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

Representative Publications

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2 May 2016 in Sensors
Verified
Journal Article
Open access
PDF file
LJLee Jonguk
Lee Jonguk
LJLong Jin
Long Jin
DPDaihee Park
Daihee Park
Yongwha ChungYongwha Chung
Yongwha Chung
Aggression among pigs adversely affects economic returns and animal welfare in intensive pigsties. In this study, we developed a non-invasive, inexpensive, automatic monitoring prototype system that uses a Kinect depth sensor to recognize aggressive behavior in a commercial pigpen. The method begins by extracting activity features from the Kinect depth information obtained in a pigsty. The detection and classification module, which employs two binary-classifier support vector machines in a hierarchical manner, detects aggressive activity, and classifies it into aggressive sub-types such as head-to-head (or body) knocking and chasing. Our experimental results showed that this method is effective for detecting aggressive pig behaviors in terms of both cost-effectiveness (using a low-cost Kinect depth sensor) and accuracy (detection and classification accuracies over 95.7% and 90.2%, respectively), either as a standalone solution or to complement existing methods.

16 April 2016 in Sensors
Verified
Journal Article
Open access
PDF file
LJLee Jonguk
Lee Jonguk
HCHeesu Choi
Heesu Choi
DPDaihee Park
Daihee Park
Yongwha ChungYongwha Chung
Yongwha Chung
HKHee-Young Kim
Hee-Young Kim
SYSukhan Yoon
Sukhan Yoon
Railway point devices act as actuators that provide different routes to trains by driving switchblades from the current position to the opposite one. Point failure can significantly affect railway operations, with potentially disastrous consequences. Therefore, early detection of anomalies is critical for monitoring and managing the condition of rail infrastructure. We present a data mining solution that utilizes audio data to efficiently detect and diagnose faults in railway condition monitoring systems. The system enables extracting mel-frequency cepstrum coefficients (MFCCs) from audio data with reduced feature dimensions using attribute subset selection, and employs support vector machines (SVMs) for early detection and classification of anomalies. Experimental results show that the system enables cost-effective detection and diagnosis of faults using a cheap microphone, with accuracy exceeding 94.1% whether used alone or in combination with other known methods.

25 September 2013 in Sensors
Verified
Journal Article
Open access
PDF file
Yongwha ChungYongwha Chung
Yongwha Chung
SOSeunggeun Oh
Seunggeun Oh
LJLee Jonguk
Lee Jonguk
DPDaihee Park
Daihee Park
HCHonghee Chang
Honghee Chang
SKSuk Kim
Suk Kim
Automatic detection of pig wasting diseases is an important issue in the management of group-housed pigs. Further, respiratory diseases are one of the main causes of mortality among pigs and loss of productivity in intensive pig farming. In this study, we propose an efficient data mining solution for the detection and recognition of pig wasting diseases using sound data in audio surveillance systems. In this method, we extract the Mel Frequency Cepstrum Coefficients (MFCC) from sound data with an automatic pig sound acquisition process, and use a hierarchical two-level structure: the Support Vector Data Description (SVDD) and the Sparse Representation Classifier (SRC) as an early anomaly detector and a respiratory disease classifier, respectively. Our experimental results show that this new method can be used to detect pig wasting diseases both economically (even a cheap microphone can be used) and accurately (94% detection and 91% classification accuracy), either as a standalone solution or to complement known methods to obtain a more accurate solution.

29 November 2017 in Sensors
Verified
Journal Article
Open access
PDF file
KJKim Jinseong
Kim Jinseong
YCYeonwoo Chung
Yeonwoo Chung
YCYounchang Choi
Younchang Choi
JSJaewon Sa
Jaewon Sa
HKHeegon Kim
Heegon Kim
HKHakjae Kim
Hakjae Kim
In a surveillance camera environment, the detection of standing-pigs in real-time is an important issue towards the final goal of 24-h tracking of individual pigs. In this study, we focus on depth-based detection of standing-pigs with “moving noises”, which appear every night in a commercial pig farm, but have not been reported yet. We first apply a spatiotemporal interpolation technique to remove the moving noises occurring in the depth images. Then, we detect the standing-pigs by utilizing the undefined depth values around them. Our experimental results show that this method is effective for detecting standing-pigs at night, in terms of both cost-effectiveness (using a low-cost Kinect depth sensor) and accuracy (i.e., 94.47%), even with severe moving noises occluding up to half of an input depth image. Furthermore, without any time-consuming technique, the proposed method can be executed in real-time.

1 May 2016 in Electronics Letters
Verified
Journal Article
Open access
PDF file
HKH. Kim
H. Kim
JSJ. Sa
J. Sa
Yongwha ChungYongwha Chung
Yongwha Chung
DPD. Park
D. Park
SYS. Yoon
S. Yoon
A practical condition monitoring method is proposed for the fault diagnosis of railway point machines (RPMs) by considering the difficulty of obtaining in‐field failure data. Failures in RPMs have a significant effect on railway train operations, and it is very crucial to detect abnormal conditions in RPMs. However, it is generally difficult to obtain in‐field failure data for a classifier training step. A diagnosis method using dynamic time warping is proposed to manage the variation in durations of RPM movement without a training step. On the basis of the experimental results with RPMs operated in Korea, it is believed that the proposed method without a training step can detect abnormal electric‐current shapes more accurately than previous training‐based methods.

25 November 2019 in IEEE Access
Verified
Journal Article
Open access
Sungju LeeSungju Lee
Sungju Lee
HAHanse Ahn
Hanse Ahn
JSJiHyun Seo
JiHyun Seo
Yongwha ChungYongwha Chung
Yongwha Chung
DPDaihee Park
Daihee Park
Sung Bum PanSung Bum Pan
Sung Bum Pan
Taking care of individual pigs is important in the management of a group-housed pig farm. However, this is nearly impossible in a large-scale pig farm owing to the shortage of farm workers. Therefore, we propose an automatic monitoring method in this study to solve the management problem of a large-scale pig farm. Particularly, we aim to detect undergrown pigs in group-housed pig rooms by using deep-learning-based computer vision techniques. Because the typical deep learning techniques require a large computational overhead (i.e., Mask-R-CNN), fast and accurate detection of undergrown pigs on an IoT-based embedded device is very challenging. We first obtain the video monitoring data of grouphoused pigs by using a top-view camera that is installed in the pig room, and then detect each moving pig by combining image processing and deep learning techniques. Gaussian Mixture Model is used to detect moving frames and moving objects. In embedded device implementations, by applying deep learning (i.e., TinyYOLO3) only to a few frames with a large number of pixel changes, embedded GPUs can be used efficiently, satisfying the real-time requirement. As a subsequent step, we check the acceptable conditions of the posture and separability from each video frame of the continuous video stream. Finally, to compute the relative size of each pig quickly and accurately, we develop image processing steps to complement the result of deep learning with minimum computational overhead. Furthermore, by pipelining the CPU and GPU steps of a continuous video stream, we can hide the additional image processing time. Based on the experimental results obtained from an embedded device, we confirm that the proposed method can automatically detect undergrown pigs in real-time, by working as an early warning system without any human inspection or measurement of actual weight by a farm worker.