• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.542-545
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• 2022

Recently, the Act on the Punishment of Severe Disasters has drawn attention to the construction environment. A common way to check the safety management of the construction site is for workers to check the site with their own eyes. However, this method is inevitably affected by the limitations of workers' abilities, resulting in fatigue and reduced work efficiency. For this reason, it cannot be an efficient method. Thus, we intend to help the working environment and construction site safety through this study, by proposing an efficient ICT safety management system that can supplement the above methods. In this paper explain the design of the access management system using RFID and the field information monitoring method through noise sensors and fine dust sensors. In addition, we propose a system that can prevent accidents between heavy equipment and people with a PIR sensor, and prevent safety accidents by grasping the slope of the building being worked through a gyro sensor.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.502-507
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• 2010

Introduction: This study examined the genetic influence of mandibular prognathism epidemiologically in Korean families. Materials and Methods: Over a 5-year period from 2005 to 2009, a questionnaire with a pedigree chart was given to 100 (male 51, female 49) probands with skeletal Class III mandibular prognathism, who had undergone orthognathic surgery in Samsung Medical Center. Results: The average age of the probands was 22.1. The average SNA, SNB and ANB angles of the probands were $81.2^{\circ}$, $84.1^{\circ}$ and $-2.9^{\circ}$, respectively. A total of 2729 (male 1,354, female 1,375) family members were examined, and the affected ratio of the families was 3.5% with no significant difference between genders. 45% of families had at least one member with a Class III malocclusion other than the proband. The affected ratio of the first-degree relatives (10.9%) was significantly higher than those of the second-degree (3.3%) and third-degree (1.9%) relatives. The affected ratio of the total relatives from the male probands (4.2%) was significantly higher than that of the female probands (2.8%). Heritability ($h^2$, Falconer' method) was estimated to be 29.8% ($0.298{\pm}0.059$) in first-degree relatives. Conclusion: These results showed the significant influence of mandibular prognathism with relatively low heritability in first-degree relatives in Korean families of probands, who had undergone orthognathic surgery to correct a skeletal Class III malocclusion.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.13-13
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• 2009

현재 열간단조 금형을 제작함에 있어 육성용접을 실시하는 방법이 금형강 STD61, STD11 등으로 제작하는 방법에 비해 보수나 비용적인 측면에서 이점을 가지고 있기 때문에 점차적으로 증가하고 있는 추세이다. 열간단조 공정에서 금형은 $1000^{\circ}C$이상의 고온재료와 반복접촉하게 된다. 이때 이형제의 사용은 급속냉각 및 급속가열의 열피로를 가속시킨다. 또한, 금형은 반복충격에 의한 기계적 피로를 받게 된다. 이러한 금형의 사용환경을 고려한 FCW는 종래 고가의 $2.8{\sim}3.2{\Phi}$인 외국산 FCW를 사용하였으나 이를 대체한 $3.2{\Phi}$ 태경 FCW가 국내에서 개발되었다. 하지만 개발된 FCW를 사용하여 제작된 금형의 수명이 부족한 현상이 발생하였다. 이에 금형의 수명을 연장시킬 수 있는 내균열성 및 내열충격성을 확보한 태경 FCW의 개발과 개발된 FCW의 성능평가가 요구되었다. 특히 열간단조 금형에 있어서 중요한 내열충격성의 경우 가열과 냉각의 반복 Cycle에 의한 Thermal shock의 평가가 대부분이며 높은 Cycle로 인해 많은 시간이 걸리며, 또한 가열과 냉각을 오갈 수 있는 고가의 시험장치가 요구된다. 그러므로 개발된 FCW 육성용접부의 내균열성 및 내열충격성을 평가할 수 있는 방법에 대한 연구와 특히 내열충격성을 시간이 적게 걸리면서도 경제적으로 평가할 수 있는 방법에 대한 연구가 필요하다. 본 연구의 목적은 열간단조 금형 육성용접부의 내균열성 및 열충격특성을 평가할 수 있는 방법에 대한 검토와 특히 내열충격성에 대해 J.W.Kim등의 시험방법을 참고하여 시간이 적게 걸리면서 저 비용으로 열 충격특성을 평가할 수 있는 시험법을 고안하는 것이다. 이를 위한 방법으로 육성용접부의 내균열성을 평가하기 위한 상온 Bending을 실시하였고, 내열충격성을 평가하기 위한 염욕로를 이용하는 고온 Bending을 고안하여 실시하였다. 상온 Bending, 고온 Bending 모두 3점 굽힘시험을 적용하였다. 고온 Bending의 가열방법으로는 염욕로를 사용하여 시편이 대기중에서 약 $850^{\circ}C$의 온도가 될 수 있도록 하였다. 시편은 각각 열처리를 하여 요구 경도를 확보하였고, 이를 염욕로에서 5분간 가열 및 유지하여 취출 후 굽힘하중을 가하여 변위의 정도로 열충격을 평가하는 방법을 사용하였다. 상온 Bending은 극한변형량과 파단부 극한응력으로, 고온 Bending은 고온 극한변형량으로 평가를 하였고, 외국산 FCW를 사용한 육성용접부를 비교대상으로 하였다. 평가 결과 개발된 국산 $3.2{\Phi}$ 태경 FCW의 성능은 외국산 FCW와 유사하거나 우수한 것으로 평가되었고, 실제 금형을 제작하여 현장에 적용한 결과 금형의 수명이 연장된 것이 나타났다.

• Restorative Dentistry and Endodontics
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• v.35 no.1
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• pp.30-39
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• 2010

This study evaluated the influence of the type of restoration and the amount of interdental spacing on the stress distribution in maxillary central incisors restored by means of porcelain laminate veneers and direct composite resin restorations. Three-dimensional finite element models were fabricated to represent different types of restorations. Four clinical situations were considered. Type I, closing diastema using composite resin. Labial border of composite resin was extended just enough to cover the interdental space; Type II, closing diastema using composite resin without reduction of labial surface. Labial border of composite resin was extended distally to cover the half of the total labial surface; Type III, closing diastema using composite resin with reduction of labial surface. Labial border of the preparation and restored composite resin was extended distally two-thirds of the total labial surface; Type IV, closing diastema using porcelain laminate veneer with a feathered-edge preparation technique. Four different interdental spaces (1.0, 2.0. 3.0, 4.0 mm) were applied for each type of restorations. For all types of restoration, adding the width of free extension of the porcelain laminate veneer and composite resin increased the stress occurred at the bonding layer. The maximum stress values observed at the bonding layer of Type IV were higher than that of Type I, II and III. However, the increasing rate of maximum stress value of Type IV was lower than that of Type I, II and III.

• The korean journal of orthodontics
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• v.50 no.1
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• pp.33-41
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• 2020

Objective: To investigate the distribution and phenotypes of hemifacial microsomia (HFM) and its association with other anomalies. Methods: This study included 249 Korean patients with HFM, whose charts, photographs, radiographs, and/or computed tomography scans acquired during 1998-2018 were available from Seoul National University Hospital and Dental Hospital. Prevalence according to sex, side involvement, degree of mandibular deformity, compensatory growth of the mandibular body, and Angle's classification, and its association with other anomalies were statistically analyzed. Results: Prevalence was not different between male and female patients (55.0% vs. 45.0%, p > 0.05). Unilateral HFM (UHFM) was more prevalent than bilateral HFM (BHFM) (86.3% vs. 13.7%, p < 0.001). Although distribution of the Pruzansky-Kaban types differed significantly in patients with UHFM (I, 53.0%; IIa, 18.6%; IIb, 24.7%; III, 3.7%; p < 0.001), no difference was observed in occurrence between the right and left sides (52.6% vs. 47.4%, p > 0.05). Among patients with BHFM, prevalence of different Pruzansky-Kaban types on the right and left sides was greater than that of the same type on both sides (67.6% vs. 32.4%, p < 0.05). Despite hypoplasia of the condyle/ramus complex, compensatory growth of the mandibular body on the ipsilateral side occurred in 35 patients (14.1%). Class I and II molar relationships were more prevalent than Class III molar relationships (93.2% vs. 6.8%, p < 0.001). Forty-eight patients (19.3%) had other anomalies, with 50.0% and 14.4% in the BHFM and UHFM groups (p < 0.001). Conclusions: Patients with HFM require individualized diagnosis and treatment planning because of diverse phenotypes and associations with other anomalies.

• The korean journal of orthodontics
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• v.52 no.1
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• pp.66-74
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• 2022

Objective: To investigate demographic and skeletodental characteristics of one-jaw (1J-OGS) and two-jaw orthognathic surgery (2J-OGS) in patients with skeletal Class III malocclusion. Methods: 750 skeletal Class III patients who underwent OGS at 10 university hospitals in Korea between 2015 and 2019 were investigated; after dividing them into the 1J-OGS (n = 186) and 2J-OGS groups (n = 564), demographic and skeletodental characteristics were statistically analyzed. Results: 2J-OGS was more frequently performed than 1J-OGS (75.2 vs. 24.8%), despite regional differences (capital area vs. provinces, 86.6 vs. 30.7%, p < 0.001). Males outnumbered females, and their mean operation age was older in both groups. Regarding dental patterns, the most frequent maxillary arch length discrepancy (ALD) was crowding in the 1J-OGS group (52.7%, p < 0.001) and spacing in the 2J-OGS group (40.4%, p < 0.001). However, the distribution of skeletal pattern was not significantly different between the two groups (all p > 0.05). The most prevalent skeletal patterns in both groups were hyper-divergent pattern (50.0 and 54.4%, respectively) and left-side chin point deviation (both 49.5%). Maxillary spacing (odds ratio [OR], 3.645; p < 0.001) increased the probability of 2J-OGS, while maxillary crowding (OR, 0.672; p < 0.05) and normo-divergent pattern (OR, 0.615; p < 0.05) decreased the probability of 2J-OGS. Conclusions: In both groups, males outnumbered females, and their mean operation age was older. The most frequent ALD was crowding in the 1J-OGS group, and spacing in the 2J-OGS group, while skeletal characteristics were not significantly different between the two groups.

• Korean Circulation Journal
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• v.52 no.6
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• pp.444-454
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• 2022

Background and Objectives: The aim of this study was to demonstrate the efficacy and safety of treatment with drug-coated balloon (DCB) in a large real-world population. Methods: Patients treated with DCBs were included in a multicenter observational registry that enrolled patients from 18 hospitals in Korea between January 2009 and December 2017. The primary outcome was target lesion failure (TLF) defined as a composite of cardiovascular death, target vessel myocardial infarction, and clinically indicated target lesion revascularization at 12 months. Results: The study included 2,509 patients with 2,666 DCB-treated coronary artery lesions (1,688 [63.3%] with in-stent restenosis [ISR] lesions vs. 978 [36.7%] with de novo lesions). The mean age with standard deviation was 65.7±11.3 years; 65.7% of the patients were men. At 12 months, the primary outcome, TLF, occurred in 179 (6.7%), 151 (8.9%), 28 (2.9%) patients among the total, ISR, and de novo lesion populations, respectively. A history of hypertension, diabetes, acute coronary syndrome, previous coronary artery bypass graft, reduced left ventricular ejection fraction, B2C lesion and ISR lesion were independent predictors of 12 months TLF in the overall study population. Conclusions: This large multicenter DCB registry study revealed the favorable clinical outcome of DCB treatment in real-world practice in patient with ISR lesion as well as small de novo coronary lesion.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.33 no.3
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• pp.172-178
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• 2022

Background and Objectives Injection laryngoplasty is a common method for treatment of unilateral vocal fold paralysis. Unilateral vocal fold paralysis has various causes, including idiopathic, infection, stroke, neurologic condition, surgery and nerve invasion by cancer. To the knowledge of the authors, there was no study on the relationship between the causes of vocal cord paralysis and the outcome of injection laryngoplasty. Therefore, we tried to investigate the difference in the outcomes of injection laryngoplasty between vocal cord paralysis after surgery group and nerve invasion by cancer group. Materials and Method A retrospective analysis was performed for 24 patients who underwent vocal cord injection due to unilateral vocal cord paralysis caused by surgery or nerve invasion by cancer. The objective quality of the voice was assessed by acoustic voice analysis with the Multi-Dimensional Voice Program. Results Both group showed an improvement of fundamental frequemcy (F0), jitter percent, shimmer (percent), and noise to hearmonic ratio (NHR) after injection laryngoplasty. The vocal cord paralysis due to nerve invasion group showed more improvement in both the mean and median value of F0, shimmer percent and NHR than the vocal cord paralysis due to surgery group, but there was not statistically significant. Conclusion Our study did not show a statistically significant difference in outcome between vocal cord paralysis due to cancer invasion group and surgery group, but statistically tendency was suggested. The vocal cord paralysis due to nerve invasion group showed more improvement in both the mean and median value of acoustic voice analysis than surgery group.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.358-366
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• 2023

This study aimed to provide a solution for improving ship collision alert of the 'accident vulnerable ship monitoring service' among the 'intelligent marine traffic information system' services of the Ministry of Oceans and Fisheries. The current ship collision alert uses a supervised learning (SL) model with survey labels based on large ship-oriented data and its operators. Consequently, the small ship data and the operator's opinion are not reflected in the current collision-supervised learning model, and the effect is insufficient because the alarm is provided from a longer distance than the small ship operator feels. In addition, the supervised learning (SL) method requires a large number of labeled data, and the labeling process requires a lot of resources and time. To overcome these limitations, in this paper, the classification model of collision alerts for small ships using unlabeled data with the semi-supervised learning (SSL) algorithms (Label Propagation and TabNet) was studied. Results of real-time experiments on small ship operators using the classification model of collision alerts showed that the satisfaction of operators increased.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.1
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• pp.9-15
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• 2012

Worldwide development of harmful algal blooms causes serious problem for public health and fisheries industries. To evaluate the algicidal impact on the harmful algae bloom species in aquatic ecosystems of coast, a new algicide thiazolidinedione derivative (TD49) were tentatively examined in the growth stages (i.e., lag, logarithmic and stationary phase) of rapidophyceae $Heterosigma$ $akashiwo$, $Chattonella$ $marina$ and $Chattonella$ sp..Three strains could easily destroy in the lag phase due to relatively weak cell walls than those of the logarithmic and stationary phase. It is thought that inoculation of TD49 substances into initial or developmental natural blooms with a threshold concentration ($2{\mu}M$) can maximize the algicidal activity. Also, bio-chemical assays revealed that the algicidal substances from all culture strains were likely to be extracellular substances because those cells have easily destroyed in cell walls. On the other hand, natural zooplankton communities were influenced within the exposure experiments of $2{\mu}M$, which is showed the maximum algcidal activity of tested organisms. These results indicate that although the TD49 substance is potential agents for the control of $H.$ $akashiwo$, $C.$ $marina$ and $Chattonella$ sp. in the enclosed eutrophic bay and coastal water, more detailed research of acute toxicity effect on high trophic organism in marine ecosystems need to be conducted.