Privacy-preserving Federated Bayesian Learning of a Generative Model for Imbalanced Classification of Clinical Data

Seok-Ju Hahn,Junghye Lee 대한산업공학회 2019 대한산업공학회 추계학술대회논문집 Vol.2019 No.11

In clinical research, the lack of events of interest often necessitates imbalanced learning. One approach to resolve this obstacle is data integration or sharing, but due to privacy concerns neither is practical. Therefore, there is an increasing demand for a platform on which an analysis can be performed in a federated environment while maintaining privacy. However, it is quite challenging to develop a federated learning algorithm that can address both privacypreserving and class imbalanced issues. In this study, we introduce a federated generative model learning platform for generating samples in a data-distributed environment while preserving privacy. We specifically propose approximate Bayesian computation-based Gaussian Mixture Model called ‘Federated ABCGMM’, which can oversample data in a minor class by estimating the posterior distribution of model parameters across institutions in a privacy-preserving manner. PhysioNet2012, a dataset for prediction of mortality of patients in an Intensive Care Unit (ICU), was used to verify the performance of the proposed method. Experimental results show that our method boosts classification performance in terms of F1 score up to nearly an ideal situation. It is believed that the proposed method can be a novel alternative to solving class imbalance problems.

Genotyping, Phage Typing, and Antimicrobial Resistance of Salmonella Typhimurium Isolated from Pigs, Cattle, and Humans

Ju, Min-Seok,Kang, Zheng-Wu,Jung, Ji-Hun,Cho, Seong-Beom,Kim, Sung-Hun,Lee, Young-Ju,Hong, Chong-Hae,Pak, Son-Il,Hahn, Tae-Wook Korean Society for Food Science of Animal Resource 2011 한국축산식품학회지 Vol.31 No.1

Salmonella enterica serovar Typhimurium (ST) is one of the most common serovars isolated from humans and animals. It has been suggested that ST infections in Koreans are largely due to the consumption of contaminated pork and beef. To investigate the genotypes, phage types, and antimicrobial resistance patterns for ST isolates of different origins, a total of 70 ST strains, including 19 isolates from humans, 44 isolates from pigs, and 6 isolates from cattle, were analyzed using pulsedfield gel electrophoresis (PFGE), phage typing, and antimicrobial susceptibility tests. Forty-three distinct PFGE patterns were generated from 70 ST isolates, which were grouped into 14 PFGE groups (from A to N) at the level of 75% similarity. The most prevalent group was the A (A1-A17 subtypes) group, encompassing 54.5% (38/70) of ST isolates. ST isolates from pigs and cattle mostly belong to groups A and L, whereas ST isolates from humans mostly belong to groups F and C. Antimicrobial susceptibility tests using 11 antimicrobial agents showed that resistance to tetracycline (TE) (81.4%) was highly prevalent, followed by streptomycin (S) (64.3%) and nalidixic acid (NA) (31.4%) resistance. A total of seventeen antimicrobial resistance patterns were observed. Only 8.6% of isolates, including a reference strain, were susceptible to all antimicrobial agents tested. The most prevalent resistance pattern was TE-S (37.1%), which was seen in 66.6% of bovine, 40.8% of swine and 21.1% of human isolates. Three ST isolates from humans (15.9%) showed resistance to 7-8 antimicrobials. The most predominant phage type (PT) was U302 (64.3%), followed by DT170 (10.0%). PFGE types did not coincide with antimicrobial resistance patterns and phage types; therefore, the combination of those types allowed for further differentiation between tested ST isolates.

Federated Learning with Learned Sufficient Statistic and Generative Models

Seok-Ju Hahn(한석주),Junghye Lee(이정혜) 한국경영과학회 2021 한국경영과학회 학술대회논문집 Vol.2021 No.6

Federated Learning with Learned Sufficient Statistic and Generative Models

Seok-Ju Hahn(한석주),Junghye Lee(이정혜) 대한산업공학회 2021 대한산업공학회 춘계학술대회논문집 Vol.2021 No.6

Learning a Personalized Subspace for Federated Learning

Seok-Ju Hahn,Minwoo Jeong,Junghyee Lee 대한산업공학회 2021 대한산업공학회 추계학술대회논문집 Vol.2021 No.11

Fairness-aware Adaptive Decision Making for Fair Federated Learning

Seok-Ju Hahn,Gi-Soo Kim,Junghye Lee 대한산업공학회 2023 대한산업공학회 추계학술대회논문집 Vol.2023 No.11

Genotyping, Phage Typing, and Antimicrobial Resistance of Salmonella Typhimurium Isolated from Pigs, Cattle, and Humans

Min Seok Ju,Zheng Wu Kang,Ji Hun Jung,Seong Beom Cho,Sung Hun Kim,Young Ju Lee,Chong Hae Hong,Son Il Pak,Tae Wook Hahn 한국축산식품학회 2011 한국축산식품학회지 Vol.31 No.1

Salmonella enterica serovar Typhimurium (ST) is one of the most common serovars isolated from humans and animals. It has been suggested that ST infections in Koreans are largely due to the consumption of contaminated pork and beef. To investigate the genotypes, phage types, and antimicrobial resistance patterns for ST isolates of different origins, a total of 70 ST strains, including 19 isolates from humans, 44 isolates from pigs, and 6 isolates from cattle, were analyzed using pulsedfield gel electrophoresis (PFGE), phage typing, and antimicrobial susceptibility tests. Forty-three distinct PFGE patterns were generated from 70 ST isolates, which were grouped into 14 PFGE groups (from A to N) at the level of 75% similarity. The most prevalent group was the A (A1-A17 subtypes) group, encompassing 54.5% (38/70) of ST isolates. ST isolates from pigs and cattle mostly belong to groups A and L, whereas ST isolates from humans mostly belong to groups F and C. Antimicrobial susceptibility tests using 11 antimicrobial agents showed that resistance to tetracycline (TE) (81.4%) was highly prevalent, followed by streptomycin (S) (64.3%) and nalidixic acid (NA) (31.4%) resistance. A total of seventeen antimicrobial resistance patterns were observed. Only 8.6% of isolates, including a reference strain, were susceptible to all antimicrobial agents tested. The most prevalent resistance pattern was TE-S (37.1%), which was seen in 66.6% of bovine, 40.8% of swine and 21.1% of human isolates. Three ST isolates from humans (15.9%) showed resistance to 7-8 antimicrobials. The most predominant phage type (PT) was U302 (64.3%), followed by DT170 (10.0%). PFGE types did not coincide with antimicrobial resistance patterns and phage types; therefore, the combination of those types allowed for further differentiation between tested ST isolates.

이륜자동차 사고에 대한 고찰

장석준,김옥준,최성욱,정원주,이한식 대한응급의학회 1997 대한응급의학회지 Vol.8 No.2

In Korea, there are about 8 million motor vehicles and one-fourth of it is motorcycle. Last year Korean government report on the motor vehicle accidents claimed 12,781 cases of motorcycle accidents and it account for 5.1% of all of motor vehicle accidents occurred in Korea. But this is too broad analysis and lack of stastical values. In general, most of people think motorcycle rider will suffer or die from head injuries sustained with motorcycle accident. Even though mandatory law on wearing helmet during motorcycle ride, but we see too many motorcycle riders not wearing helmet, especially in teenagers. The loss of young person by accident is great loss for family, society and economy of nation. No one will doubt the effectiveness of helmet on reduced incidence of head injuries. And multiple from United States of America have clearly demonstrated the benefit of helmets in motorcycle accidents. The following study was undertaken to determine the relationship between head injuries and helmet use in motorcycle accident, as well as analysis of general motorcycle accident.

Takayasu’s Arteritis Treated by Percutaneous Transluminal Angioplasty with Stenting in the Descending Aorta

Byung Ju Shim,Ho Joong Youn,Yong Chul Kim,Woo Tae Kim,Yun Seok Choi,Dong Hyun Lee,Chul Soo Park,Yong Seok Oh,정욱성,Jae Hyung Kim,Kyu Bo Choi,Soon Jo Hong,Seung Eun Jung,Seong Tai Hahn 대한의학회 2008 Journal of Korean medical science Vol.23 No.3

A 17-yr-old young woman was referred to our hospital with a 2-yr history of claudication of the lower extremities and severe arterial hypertension. Physical examination revealed significantly different blood pressures between both arms (160/92 and 180/95 mmHg) and legs (92/61 and 82/57 mmHg). The hematological and biochemical values were within their normal ranges, except for the increased erythrocyte sedimentation rate (83 mm/hr) and C-reactive protein (6.19 mg/L). On 3- dimensional computed tomographic angiography, the ascending aorta, the aortic arch and its branches, and the thoracic and, descending aorta, but not the renal artery, were shown to be stenotic. The diagnosis of type IIb Takayasu’s arteritis was made according to the new angiographic classification of Takayasu’s arteritis, Takyasu conference 1994. Percutaneous transluminal angioplasty with stenting was performed on the thoracic and abdominal aorta. After the interventional procedures, the upper extremity blood pressure improved from 162/101 mmHg to 132/85 mmHg, respectively. She has been free of claudication and there have been no cardiac events during 2-yr of clinical follow-up.

뇌성마비 Crouch 보행에서 고관절 회전각에 따른 3차원 근-골격 모델에서의 근-건 길이 변화

김주영(Ju- Young Kim),김현우(Hyun- Woo Kim),이기석(Ki-Seok Lee),한수봉(Soo-Bong Hahn),박희완(Hui-Wan Park),박건보(Kun-Bo Park) 대한정형외과학회 2011 대한정형외과학회지 Vol.46 No.2

목적 : Crouch 보행은 뇌성마비 환아의 흔한 보행 이상 중의 한 가지로서 슬관절 굴곡의 호전을 위한 슬와부 근육 연장술은 crouch 보행의 치료에 있어서 기본적인 술식의 하나로 생각되어 왔다. 그러나 슬와부 근육의 길이의 단축에 있어서는 다양한 연구결과가 존재하였다. 회전면에서의 crouch보행 분류를 시행하고 각 군에서 근육의 길이를 분석하여 슬와부 근육 연장술에 대한 기준을 제시하고자 한다. 대상 및 방법 : Crouch 보행을 보이는 경직성 뇌성마비 환아 중 초기 입각기의 슬관절 굴곡이 20°이상이거나 중기 입각기의 슬관절 굴곡이 20°이상인 환아를 대상으로 하였다. 총 62명의 환아(124예)가 선별되었으며 보행 분석 지표와 중둔근, 내전근, 대퇴 직근, 대퇴 이두근, 반막양근, 박근의 길이를 비교하였다. 중기 입각기의 평균 회전을 측정한 후 정상의 ±1 표준편차 범위를 정상으로 간주하여 고관절의 회전지표에 따라 고관절 외회전(제 1군), 정상범위(제 2군), 고관절 내회전(제 3군)인 세 군으로 분류하였다. 동 연령대의 정상인 15명을 모집하여 정상군과의 비교를 시행하였다. 결과 : 제 3군에서 슬관절 및 고관절 굴곡이 가장 증가되어 있었으며 제 1군에서 족관절 배부 굴곡이 가장 감소되어 있었다. 시상명 상에 서의 모멘트 및 힘의 비교에서는 각 군간 유의한 차이가 관찰되지 않았다. 중둔근 및 대퇴 직근의 길이는 각 군간 통계상 유의한 차이가 관찰되지 않았다. 제 3군에서 내전근, 대퇴 이두근과 박근의 평균 비례 근길이가 가장 증가되어 있었으며 반막양근의 평균 비례 근길이가 가장 감소되어 있었다. 정상군과의 비교 시에는 각 군 모두 통계 상 유의한 차이가 관찰되지 않았다. 결론 : Crouch 보행을 보이는 환아에서 고관절 회전에 관계없이 슬와부 근육의 길이는 정상군과 차이가 관찰되지 않았다. 그러나 고관절 내회전이 증가된 crouch 보행의 수술 시 대퇴골 전염전에 대한 교정 절골술이 시행된다면 반막양근에 대한 연장술을 시행하는 것이 보행 호전에 유효할 것으로 생각된다. Purpose : Crouch gait is one of the common pathologic gaits in children with cerebral palsy. Hamstring lengthening for alleviation of knee flexion is often considered as a first choice for the treatment of crouch gait. However, there have been a variety of reports about the lengths of the hamstring muscle. The purpose of this study was to classify the crouch gait on the transverse plane and to suggest a guide line for hamstring lengthening by analyzing the length of these muscles. Materials and Methods : The subjects for this study were selected in ambulatory spastic diplegia patients with crouch gait. A total of sixty-two patients (124 cases) were included. The gait parameters and the muscle lengths were compared. The range of ±1 standard deviation of the normal middle stance hip rotation was considered as the normal range. The subjects were divided into three groups as hip external rotated (groupⅠ). normal (group Ⅱ) and hip internal rotated (group Ⅲ) according to the hip rotation. Results : The flexion of the knee and hip was the greatest in group Ⅲ and dorsiflexion of the ankle was the least in group Ⅰ. On comparison of moment and power on the sagittal plane, there was no significant difference among the groups. In group Ⅲ, the percent lengths of the adductor, biceps femoris and gracilis muscles were increased the most, whereas the percent length of the semimembranosus was decreased the most. There was no statistical difference between groups Ⅰ and Ⅱ and the normal control group. Conclusion : Irrespective of the hip rotation, the length of the hamstring muscle in patients with crouch gait did not differ compared to that of the normal control. But if rotational osteotomy is done for the correction of the increased femoral anteversion in group Ⅲ, then we should consider lengthening the semimembranosus muscle.