안와골절 환자의 응급의료센터 체류시간에 영향을 미치는 요인 분석

서준영,김호중,조영순,최재형,김혜선 대한응급의학회 2015 대한응급의학회지 Vol.26 No.1

Purpose: The aim of this study un to determine factors that affect Emergency department (ED) Length of Stay (LOS) in patients with orbital wall fracture. Methods: We retrospectively analyzed orbital fracture patients who visited our ED from January 1, 2012 to December 31, 2013. Patients’data, including sex, age, mechanism of injury, site of fracture, associated injury, physical finding, CT finding, and intra-ocular injuries were recorded. LOS was divided into three phases (Pre-consultation time, Consultation waiting time, Consultation time). We performed analysis to determine the factors associated with LOS. We also performed analysis to determine the factors associated with severe intraocular injury (SIOS). Results: A total of 154 patients (160 eyes) were included. Orbital fractures were more frequent in males. The most common cause of orbital fracture was violence. LOS was 290.0 (IQR 200.0~465.0) min, pre-consultation time was 36.0 (IQR 22.0~61.0) min, consultation waiting time was 64.0 (IQR 34.0~128.0) min, and consultation time was 152.0 (IQR 87.0~245.0) min. Violence, alcohol consumption, consultation with plastic surgeon, and consultation with ophthalmologist showed association with prolonged LOS (p<0.001, p<0.001, p=0.04, p<0.001). Violence and alcohol consumption affected consultation waiting time (p<0.001, p<0.001) and consultation time (p=0.04, p<0.001). Consultation with a plastic surgeon and consultation with an ophthalmologist affected consultation time (p=0.03, p<0.001). Patients with symptoms including blindness, blurred vision, and visual field defect showed significant association with SIOS (Odd ratio=14.08). Conclusion: Violence, alcohol consumption, and consultations with specialists showed significant association with LOS.

스테레오 매칭을 활용한 설비 이상 감지 모바일 로봇 개발

서준영,이주훈,이창호,유기성 제어로봇시스템학회 2023 제어로봇시스템학회 국내학술대회 논문집 Vol.2023 No.6

There have been a lot of studies in the past for the method of predicting the failure of a machine, and recently, a lot of researches and applications have been generated to diagnose the physical condition of the machine and the parts and to calculate the remaining life through various methods. Survival models are also used to predict plant failures based on past anomaly cycles. In this paper, we developed a rail-driven mobile system that diagnoses machine abnormalities by receiving machine information from images and thermal images of targets with limited operator access and inspection or requiring long-term monitoring in a wide area. This anomaly diagnosis model uses a 2D temperature array (temperature map) and a motion vector array (motion map) as inputs data of the Wasserstein GAN (wGAN) learning model trained with normal data. Because the difference between the input and output is used as a global loss function (global), the anomaly score is calculated and the condition of the machine is diagnosed according change of anomaly score. This rail-driven mobile system is expected to make a great contribution to equipment maintenance and optimal operation because it provides quantitative evidence to monitor equipment in the long term to diagnose failures early and give maintenance instructions.

Effect of Free Abrasives on Material Removal in Lap Grinding of Sapphire Substrate

서준영,김태경,이현섭 한국트라이볼로지학회 2018 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.34 No.6

Sapphire is a substrate material that is widely used in optical and electronic devices. However, the processing of sapphire into a substrate takes a long time owing to its high hardness and chemical inertness. In order to process the sapphire ingot into a substrate, ingot growth, multiwire sawing, lapping, and polishing are required. The lap grinding process using pellets is known as one of the ways to improve the efficiency of sapphire substrate processing. The lap grinding process ensures high processing efficiency while utilizing two-body abrasion, unlike the lapping process which utilizes three-body abrasion by particles. However, the lap grinding process has a high material removal rate (MRR), while its weakness is in obtaining the required surface roughness for the final polishing process. In this study, we examine the effects of free abrasives in lap grinding on the material removal characteristics of sapphire substrate. Before conducting the lap grinding experiments, it was confirmed that the addition of free abrasives changed the friction force through the pin-on-disk wear test. The MRR and roughness reduction rate are experimentally studied to verify the effects of free abrasive concentration on deionized water. The addition of free abrasives (colloidal silica) in the lap grinding process can improve surface roughness by three-body abrasion along with two-body abrasion by diamond grits.

석분슬러지 혼입이 시멘트 모르타르 특성에 미치는 물리적 영향

서준영,최선종,강수태,Seo, Jun-Yeong,Choi, Seon-Jong,Kang, Su-Tae 한국건설순환자원학회 2015 한국건설순환자원학회 논문집 Vol.3 No.2

본 연구에서는 잔골재의 일부 대체재로 석분슬러지의 활용가능성을 살펴보기 위해서, 석분슬러지 활용 시멘트 모르타르에서 석분슬러지 치환율 변화에 따른 굳지 않은 상태 물성과 강도 변화 실험을 수행하였다. 치환율은 0, 10, 20, 30%를 고려하였으며, 굳지 않은 상태 물성으로는 슬럼프, 공기량, 레올로지 특성을 평가하였으며, 강도는 압축강도 및 휨인장강도를 평가하였다. 그 결과, 슬럼프 및 공기량은 석분슬러지 치환율이 증가함에 따라 감소하는 것으로 나타났으며, 레올로지 특성에서는 치환율 20%까지는 항복응력 및 소성점도 모두 증가하는 것으로 나타났지만, 치환율 30%에서는 20%와 큰 차이가 나지 않았다. 항복응력의 경우 10%에서 20% 사이에서 증가율이 크게 나타났다. 압축강도 및 휨인장강도 결과에서는 석분슬러지 치환율에 따른 강도변화는 크게 나타나지 않았지만, 석분슬러지를 혼입할 경우 초기재령에서는 강도증진 효과가 명확히 나타났으며 28일 재령에서는 석분슬러지를 사용하지 않은 경우와 큰 차이가 없는 것으로 나타났다. In order to investigate the feasibility of stone dust sludge as fine aggregate, an experimental study was performed on cement mortar with stone dust sludge. fresh mortar properties and strength with various stone dust sludge replacement ratios were estimated. the replacement ratio adopted in this study was 0, 10, 20, 30%. Flow, air content, and rheological properties were considered as properties of fresh mortar. Compressive strength and flexural tensile strength were measured for strength. The results are as follows. Higher amount of stone dust sludge caused reduction in slump and air content. In the rheological properties, both yield stress and plastic viscosity increased as stone dust sludge content increased up to 20% replacement ratio, but there were no remarkable difference between 20 and 30%. Yield stress increased drastically between 10 and 20%. Compressive and flexural tensile strength results indicated that the strength variation was not significant according to stone dust sludge content, but the strength gain in the early age by adding stone dust sludge was evident. the strength at the age of 28 days however did not show noticeable effect of adding stone dust sludge.

카드사의 수익모델 변수를 통한 고객 세분화와 소비 행동 패턴 탐색

서준영,하진석,신민수 한국경영정보학회 2018 한국경영정보학회 학술대회논문집 Vol.2018 No.11

텍스트 마이닝을 통한 이직예측모형 탐색 연구

서준영,심유정,신민수 한국경영정보학회 2019 한국경영정보학회 학술대회논문집 Vol.2019 No.11

Flexible 기판을 사용한 복합형 화재센서의 연구

서준영,최준석,고동완,노재하,이상태,정정열,이문진,장지호 해양환경안전학회 2019 해양환경안전학회 학술발표대회 논문집 Vol.2019 No.11

간문맥 혈전증: 역학, 진단 및 치료에 관하여

서준영,김세화,유양재,이아영,박상종 대한내과학회 2023 대한내과학회지 Vol.98 No.4

In recent years, the incidence of portal vein thrombosis (PVT) in patients with cirrhosis has increased; the thrombosis ranges from asymptomatic partial to complete occlusion. Treatment is difficult. Anticoagulation therapy may be the optimal first-line treatment for patients with acute PVT who lack variceal bleeding or mesenteric ischemia. Minimally invasive treatment options include mechanical thrombectomy, chemical thrombolysis, and stent placement. However, the effectiveness and timing of anticoagulation and interventional therapies remain unclear.

Bone Mineral Density and Osteoporotic Vertebral Fractures in Traditional, Unassisted, Free-Diving Women (Haenyeos)

서준영,하기용,김영훈,김성찬,윤은지,박형율 대한의학회 2018 Journal of Korean medical science Vol.33 No.48

Background: Water pressure and muscle contraction may influence bone mineral density (BMD) in a positive way. However, divers experience weightlessness, which has a negative effect on BMD. The present study investigated BMD difference in normal controls and woman free-divers with vertebral fracture and with no fracture. Methods: Between January 2010 and December 2014, traditional woman divers (known as Haenyeo in Korean), and non-diving women were investigated. The study population was divided into osteoporotic vertebral fracture and non-fracture groups. The BMD of the lumbar spine and femoral neck was measured. The radiological parameters for global spinal sagittal balance were measured. Results: Thirty free-diving women and thirty-three non-diving women were enrolled in this study. The mean age of the divers was 72.1 ± 4.7 years and that of the controls was 72.7 ± 4.0 years (P = 0.61). There was no statistical difference in BMD between the divers and controls. In divers, cervical lordosis and pelvic tilt were significantly increased in the fracture subgroup compared to the non-fracture subgroup (P = 0.028 and P = 0.008, respectively). Sagittal vertical axis was statistically significantly correlated with cervical lordosis (Spearman's rho R = 0.41, P = 0.03), and pelvic tilt (Spearman's rho R = 0.46, P = 0.01) in divers. Conclusion: BMD did not differ significantly between divers and controls during their postmenopausal period. When osteoporotic spinal fractures develop, compensation mechanisms, such as increased cervical lordosis and pelvic tilt, was more evident in traditional woman divers. This may be due to the superior back muscle strength and spinal mobility of this group of women.

카메라를 이용한 공작물 크기 측정시스템 설계

서준영,김갑순 제어·로봇·시스템학회 2019 제어·로봇·시스템학회 논문지 Vol.25 No.9

In this paper, the workpiece size measurement system is designed to measure the size (width and height) of a workpiece using the measurement system with a camera. The system consists of a body, a vertical camera movement mechanism, a horizontal camera focus adjustment mechanism, a horizontal illumination device, a vertical illumination device, an infrared sensor, and a control device. To improve the measurement accuracy, camera calibration and image rotation calibration were performed, and image processing was performed using a subpixel algorithm. As a result of measuring the width and height of the block gauges as a reference object using the workpiece size measurement system, the width measurement accuracy was ±0.0041 mm and the height measurement accuracy was ±0.0043 mm. Therefore, it is considered that the designed workpiece size measurement system can measure a workpiece with accuracy less than ± 0.01.