Joonsoo Bae

Prof. Joonsoo Bae

orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

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

Representative Publications

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6 February 2018 in Micromachines
Verified
Journal Article
Open access
PDF file
NSNita Solehati
Nita Solehati
JBJoonsoo Bae
Joonsoo Bae
Agus SasmitoAgus Sasmito
Agus Sasmito
The micro-mixer has been widely used in mixing processes for chemical and pharmaceutical industries. We introduced an improved and easy to manufacture micro-mixer design utilizing the wavy structure micro-channel T-junction which can be easily manufactured using a simple stamping method. Here, we aim to optimize the geometrical parameters, i.e., wavy frequency, wavy amplitude, and width and height of the micro channel by utilizing the robust Taguchi statistical method with regards to the mixing performance (mixing index), pumping power and figure of merit (FoM). The interaction of each design parameter is evaluated. The results indicate that high mixing performance is not always associated with high FoM due to higher pumping power. Higher wavy frequency and amplitude is required for good mixing performance; however, this is not the case for pumping power due to an increase in Darcy friction loss. Finally, the advantages and limitations of the designs and objective functions are discussed in the light of present numerical results.

30 June 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
DLDawei Luo
Dawei Luo
IYIlhwan Yang
Ilhwan Yang
JBJoonsoo Bae
Joonsoo Bae
YWYoonhyuck Woo
Yoonhyuck Woo
Lung nodule classification is crucial for the diagnosis and treatment of lung diseases. However, selecting appropriate metrics to evaluate classifier performance is challenging, due to the prevalence of negative samples over positive ones, resulting in imbalanced datasets. This imbalance often necessitates the augmentation of positive samples to train powerful models effectively. Furthermore, specific medical tasks require tailored augmentation methods, the effectiveness of which merits further exploration based on task objectives. This study conducted a detailed analysis of commonly used metrics in lung nodule detection, examining their characteristics and selecting suitable metrics based on this analysis and our experimental findings. The selected metrics were then applied to assessing different combinations of image augmentation techniques for nodule classification. Ultimately, the most effective metric was identified, leading to the determination of the most advantageous augmentation method combinations.

3 December 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
DLDawei Luo
Dawei Luo
HZHeng Zhou
Heng Zhou
JBJoonsoo Bae
Joonsoo Bae
BYBom Yun
Bom Yun
Reliability and robustness are fundamental requisites for the successful integration of deep-learning models into real-world applications. Deployed models must exhibit an awareness of their limitations, necessitating the ability to discern out-of-distribution (OOD) data and prompt human intervention, a critical competency. While several frameworks for OOD detection have been introduced and achieved remarkable results, most state-of-the-art (SOTA) models rely on supervised learning with annotated data for their training. However, acquiring labeled data can be a demanding, time-consuming or, in some cases, an infeasible task. Consequently, unsupervised learning has gained substantial traction and has made noteworthy advancements. It empowers models to undergo training solely on unlabeled data while still achieving comparable or even superior performance compared to supervised alternatives. Among the array of unsupervised methods, contrastive learning has asserted its effectiveness in feature extraction for a variety of downstream tasks. Conversely, auto-encoders are extensively employed to acquire indispensable representations that faithfully reconstruct input data. In this study, we introduce a novel approach that amalgamates contrastive learning with auto-encoders for OOD detection using unlabeled data. Contrastive learning diligently tightens the grouping of in-distribution data while meticulously segregating OOD data, and the auto-encoder augments the feature space with increased refinement. Within this framework, data undergo implicit classification into in-distribution and OOD categories with a notable degree of precision. Our experimental findings manifest that this method surpasses most of the existing detectors reliant on unlabeled data or even labeled data. By incorporating an auto-encoder into an unsupervised learning framework and training it on the CIFAR-100 dataset, our model enhances the detection rate of unsupervised learning methods by an average of 5.8%. Moreover, it outperforms the supervised-based OOD detector by an average margin of 11%.

30 October 2023 in Journal of Society of Korea Industrial and Systems Engineering
Verified
Journal Article
Closed access
BYBom Yun
Bom Yun
JBJoonsoo Bae
Joonsoo Bae

1 January 2011
Verified
Book Chapter
Closed access
PDF file
JBJoonsoo Bae
Joonsoo Bae
NSNita Solehati
Nita Solehati
YKYoung Ki Kang
Young Ki Kang

30 September 2023 in Journal of Society of Korea Industrial and Systems Engineering
Verified
Journal Article
Closed access
JKJunki Kim
Junki Kim
JBJoonsoo Bae
Joonsoo Bae
YSYeongheon Song
Yeongheon Song
BJByungho Jeong
Byungho Jeong