챕터 단위 동영상 추천 시스템의 정확도 향상을 위한 키워드 클러스터 기반의 그래프 신경망 활용에 관한 연구

Purevsuren Chimeddorj,김두현(Doohyun Kim) 한국컴퓨터정보학회 2024 韓國컴퓨터情報學會論文誌 Vol.29 No.7

본 논문은 챕터 수준의 강의 동영상 추천 시스템에 있어서 추천의 정확도와 처리속도 간의 균형문제, 즉, 추천 정확도를 향상시키려면 처리 속도가 저하되고, 반대로 처리 속도를 높일 경우 정확도가 감소하는 문제에 대하여 연구한다. 본 논문에서는 이의 해결을 위하여 TF-IDF, K-Means++ Clustering, Graph Neural Network(GNN) 등 다양한 기법을 복합적으로 활용하는 방법을 제안한다. 즉, 챕터들의 유사성을 바탕으로 클러스터를 사전에 구성함으로써 검색 시의 계산량을 줄여 속도를 향상시키면서도, 클러스터를 노드로 하는 그래프에 대하여 GNN을 적용함으로써 추천의 정확도를 향상시키는 방법을 제안한다. 실험 결과 GNN을 사용한 경우 추천의 정확도가 MRR 지표에서 약 19.7% 증가하였으며, 유사도 기반의 정밀도에 있어서 약 27.7% 증가하는 결과를 확인할 수 있었다. 이를 통해 학습자의 질의에 보다 적합한 동영상 챕터를 추천하는 학습시스템 구축에 기여할 것으로 기대한다. In this paper, we propose a system for recommending lecture videos at the chapter level, addressing the balance between accuracy and processing speed in chapter-level video recommendations. Specifically, it has been observed that enhancing recommendation accuracy reduces processing speed, while increasing processing speed decreases accuracy. To mitigate this trade-off, a hybrid approach is proposed, utilizing techniques such as TF-IDF, k-means++ clustering, and Graph Neural Networks (GNN). The approach involves pre-constructing clusters based on chapter similarity to reduce computational load during recommendations, thereby improving processing speed, and applying GNN to the graph of clusters as nodes to enhance recommendation accuracy. Experimental results indicate that the use of GNN resulted in an approximate 19.7% increase in recommendation accuracy, as measured by the Mean Reciprocal Rank (MRR) metric, and an approximate 27.7% increase in precision defined by similarities. These findings are expected to contribute to the development of a learning system that recommends more suitable video chapters in response to learners queries.

Dynamic simulation of tibial tuberosity realignment: model evaluation.

Purevsuren, Tserenchimed,Elias, John J,Kim, Kyungsoo,Kim, Yoon Hyuk Gordon and Breach Science Publishers 2015 Computer methods in biomechanics and biomedical en Vol.18 No.14

<P>This study was performed to evaluate a dynamic multibody model developed to characterize the influence of tibial tuberosity realignment procedures on patellofemoral motion and loading. Computational models were created to represent four knees previously tested at 40, 60, and 80 of flexion with the tibial tuberosity in a lateral, medial and anteromedial positions. The experimentally loaded muscles, major ligaments of the knee, and patellar tendon were represented. A repeated measures ANOVA with post-hoc testing was performed at each flexion angle to compare data between the three positions of the tibial tuberosity. Significant experimental trends for decreased patella flexion due to tuberosity anteriorization and a decrease in the lateral contact force due to tuberosity medialization were reproduced computationally. The dynamic multibody modeling technique will allow simulation of function for symptomatic knees to identify optimal surgical treatment methods based on parameters related to knee pathology and pre-operative kinematics.</P>

Fatigue injury risk in anterior cruciate ligament of target side knee during golf swing

Purevsuren, Tserenchimed,Kwon, Moon Seok,Park, Won Man,Kim, Kyungsoo,Jang, Seung Ho,Lim, Young-Tae,Kim, Yoon Hyuk Elsevier 2017 Journal of biomechanics Vol.53 No.-

<P><B>Abstract</B></P> <P>A golf-related ACL injury can be linked with excessive golf play or practice because such over-use by repetitive golf swing motions can increase damage accumulation to the ACL bundles. In this study, joint angular rotations, forces, and moments, as well as the forces and strains on the ACL of the target-side knee joint, were investigated for ten professional golfers using the multi-body lower extremity model. The fatigue life of the ACL was also predicted by assuming the estimated ACL force as a cyclic load. The ACL force and strain reached their maximum values within a short time just after ball-impact in the follow-through phase. The smaller knee flexion, higher internal tibial rotation, increase of the joint compressive force and knee abduction moment in the follow-through phase were shown as to lead an increased ACL loading. The number of cycles to fatigue failure (fatigue life) in the ACL might be several thousands. It is suggested that the excessive training or practice of swing motion without enough rest may be one of factors to lead to damage or injury in the ACL by the fatigue failure. The present technology can provide fundamental information to understand and prevent the ACL injury for golf players.</P>

Prediction of medial and lateral contact force of the knee joint during normal and turning gait after total knee replacement

Purevsuren, Tserenchimed,Dorj, Ariunzaya,Kim, Kyungsoo,Kim, Yoon Hyuk SAGE Publications 2016 Proceedings of the Institution of Mechanical Engin Vol.230 No.4

<P>The computational modeling approach has commonly been used to predict knee joint contact forces, muscle forces, and ligament loads during activities of daily living. Knowledge of these forces has several potential applications, for example, within design of equipment to protect the knee joint from injury and to plan adequate rehabilitation protocols, although clinical applications of computational models are still evolving and one of the limiting factors is model validation. The objective of this study was to extend previous modeling technique and to improve the validity of the model prediction using publicly available data set of the fifth Grand Challenge Competition to Predict In Vivo Knee Loads. A two-stage modeling approach, which combines conventional inverse dynamic analysis (the first stage) with a multi-body subject-specific lower limb model (the second stage), was used to calculate medial and lateral compartment contact forces. The validation was performed by direct comparison of model predictions and experimental measurement of medial and lateral compartment contact forces during normal and turning gait. The model predictions of both medial and lateral contact forces showed strong correlations with experimental measurements in normal gait (r=0.75 and 0.71) and in turning gait trials (r=0.86 and 0.72), even though the current technique over-estimated medial compartment contact forces in swing phase. The correlation coefficient, Sprague and Geers metrics, and root mean squared error indicated that the lateral contact forces were predicted better than medial contact forces in comparison with the experimental measurements during both normal and turning gait trials.</P>

교정치료의 불편함과 일상활동에 대한 구강 내 영향

Purevsuren Batkhuyag,이상민(Sang-Min Lee),정동화(Dong-Hwa Chung),이진우(Jin-Woo Lee) 대한치과교정학회 2021 대한치과교정학회 임상저널 Vol.11 No.3

Introduction: The main purpose of this study was to compare (1) discomfort during orthodontic treatment; and (2) Oral Impact on Daily Performance (OIDP) among different genders and age groups. Methods: This study involved 89 participants (47 adolescents, 42 adults) who were undergoing orthodontic fixed appliance treatment. Data was collected using two questionnaires - the OIDP questionnaire and discomfort during orthodontic treatment questionnaire. The OIDP questionnaire consisted of 8-items that evaluated the impact of oral conditions on an individual’s ability to perform daily activities; the discomfort during orthodontic treatment questionnaire consisted of twelve questions relating to the treatment experience. Results: Questionnaire responses showed that the most uncomfortable part of orthodontic treatment was ‘It is uncomfortable when the dental instrument is pressed against my gum and lips.’ There were no statistically significant differences between the two groups in discomfort during orthodontic treatment questionnaire. For the OIDP questionnaire, the scores related to physical performance were the highest compared to psychosocial and social performance in both groups. Out of the eight questions in the OIDP questionnaire, ‘Social contact’ had a much higher score in the adult group (0.48 ± 0.71) than in the adolescent group (0.19 ± 0.40) (P=0.02). Conclusions: In mostcases,discomfortwasrelatedto the use of dentalinstruments, which therefore show that the design ofdentalinstruments should be improved. Also, this study showed that the discomfort caused by orthodontic treatment on daily activities had a larger impact, causing more inconvenience compared to the discomfort during the actual orthodontic treatment in the dental clinic.

Contribution of Posterolateral Corner Structures to Knee Joint Translational and Rotational Stabilities

Purevsuren Tserenchimed,Yoon Hyuk Kim 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

IL-5 Promoter Polymorphism Enhances IgE Responses to Staphylococcal Superantigens in Adult Asthmatics

Purevsuren Losol,김승현,황의경,신유섭,박해심 대한천식알레르기학회 2013 Allergy, Asthma & Immunology Research Vol.5 No.2

Interleukin 5 (IL-5) is a key cytokine involved in the induction of T-helper type 2 (Th2) responses in the asthmatic airway. We investigated IL-5 geneticpolymorphisms associated with asthma phenotypes, including IgE responses to staphylococcal enterotoxins A and B (SEA and SEB, respectively), inasthmatics. Adult asthmatics (n=310) and normal controls (n=160) were enrolled in the present study. Serum total and specific IgE to SEA and SEBwere measured. Two IL-5 polymorphisms, -746A>G and +4499T>G, were genotyped using the primer-extension method. There were no significantdifferences in genotype or haplotype frequencies of these polymorphisms between the two groups. Asthmatics carrying the AG/GG genotype at-746A>G had a significantly higher prevalence of serum specific IgE to SEA (P=0.008), higher total IgE levels (P=0.014), and lower PC20 methacholinelevels (P=0.002) compared to those with the AA genotype. These findings suggest that the IL-5 promoter polymorphism at -746A>G enhancesserum total and specific IgE responses to SEA, which may augment airway hyperresponsiveness in adult asthmatics.

A genetic effect of IL-5 receptor a polymorphism in patients with aspirin-exacerbated respiratory disease

Purevsuren Losol,김승현,Yoo Seob Shin,예영민,박해심 생화학분자생물학회 2013 Experimental and molecular medicine Vol.45 No.3

Persistent eosinophil activation in both the upper and lower airway mucosa is a central feature of aspirin-exacerbated respiratory disease (AERD). Eosinophil activation and survival are profoundly influenced by interleukin 5 (IL-5) and its receptor, IL-5R. In patients susceptible to allergic disorders, IL-5 receptor a (IL5RA) polymorphisms have been reported;however, an association with AERD remains unclear. We hypothesize that IL5RA polymorphisms may contribute to eosinophil activation in AERD patients. We recruited 139 AERD patients, 171 aspirin-tolerant asthma patients and 160 normal controls. IL5RA polymorphisms (5993G4A, 5567C4G and 5091G4A) were genotyped and functional activity of polymorphism was assessed by luciferase reporter assay and electrophoretic mobility shift assay (EMSA). There was no significant difference in the genotype frequency of the three polymorphisms among the three groups. AERD patients carrying the AA genotype at 5993G4A had a significantly higher presence of serum-specific immunoglobulin E (IgE) to staphylococcal enterotoxin A (P¼0.008) than those with the GG/GA genotype. In vitro, the 5993A allele had a higher promoter activity compared with the 5993G allele in human mast cell (HMC-1; P¼0.030) and human promyelocytic leukemia (HL-60; P¼0.013) cells. In EMSA, a 5993A probe produced a specific shifted band than the 5993G had. These findings suggest that a functional polymorphism in IL5RA may contribute to eosinophil and mast cell activation along with specific IgE responses to staphylococcal enterotoxin A in AERD patients.

Biomechanical Factors Leading to High Loading in the Anterior Cruciate Ligament of the Lead Knee During Golf Swing

Tserenchimed Purevsuren,Batbayar Khuyagbaatar,SuKyoung Lee,Yoon Hyuk Kim 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.2

For golf swing, the soft tissue structure resisting joint compression and internal rotation of the knee at low flexion angle may be susceptible for a lead knee injury. Therefore, anterior cruciate ligament (ACL) rupture is one of the potential injuries that may occur from repeated stress during golf. The current study was purposed to investigate the biomechanical factors that lead to high ACL load in the lead knee during golf swing. The joint kinematic data of the lead leg and trunk, joint kinetic data of the lead knee, ground reaction force, and the external knee moments were compared between the low and high ACL loading groups. The results demonstrated an increased amount of frontal plane moment arm and external knee adduction (varus) moment just after ball impact for the high ACL loading group. These observations were associated with a characteristic difference in the upper body motion and were the main contributors to the elevated ACL force of the lead knee. The mechanism that generates a high amount of ACL loading during golf swing, which involves the application of external knee adduction moment just after ball impact, may differ from conventional non-contact ACL injury mechanisms that associated with dynamic valgus loading during injury circumstance.

Molecular Genetic Mechanisms of Chronic Urticaria

Losol, Purevsuren,Yoo, Hye-Soo,Park, Hae-Sim The Korean Academy of Asthma, Allergy and Clinical 2014 Allergy, Asthma & Immunology Research Vol.6 No.1

<P>Chronic urticaria (CU) is a common allergic skin disease that requires long-term pharmacological treatment. Some patients with severe CU suffer a poor quality of life. Although the pathogenic mechanisms of CU are not clearly understood, several groups have suggested that genetic mechanisms are involved in various CU cohorts. To further understand the molecular genetic mechanisms of CU, we summarize recent genetic data in this review. Although a few HLA alleles were suggested to be candidate markers in different ethnic groups, further replication studies that apply the recent classification are needed. Genetic polymorphisms in histamine-related genes, including <I>FcεRI</I> and <I>HNMT</I>, were suggested to be involved in mast cell activation and histamine metabolism. Several genetic polymorphisms of leukotriene-related genes, such as <I>ALOX5</I>, <I>LTC4S</I>, and the PGE2 receptor gene <I>PTGER4</I>, were suggested to be involved in leukotriene overproduction, a pathogenic mechanism. Further investigations using candidate gene approaches and genome-wide association studies (GWAS) will provide new insights into the molecular genetic mechanisms of CU, which will provide new marker genes for differentiation of CU phenotypes and identification of potential therapeutic targets.</P>