• 자동차안전학회지
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• 제14권2호
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• pp.57-69
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• 2022

Recently, as interest in self-driving cars has increased worldwide, research and development on the Advanced Driver Assist System is actively underway. Among them, the purpose of Adaptive Cruise Control (ACC) is to minimize the driver's driving fatigue through the control of the vehicle's longitudinal speed and relative distance. In this study, for the research of the ACC test in the real environment, the real-road test was conducted based on domestic-road test scenario proposed in preceding study, considering ISO 15622 test method. In this case, the distance measurement method using the dual camera was verified by comparing and analyzing the result of using the dual camera and the result of using the measurement equipment. As a result of the comparison, two results could be derived. First, the relative distance after stabilizing the ACC was compared. As a result of the comparison, it was found that the minimum error rate was 0.251% in the first test of scenario 8 and the maximum error rate was 4.202% in the third test of scenario 9. Second, the result of the same time was compared. As a result of the comparison, it was found that the minimum error rate was 0.000% in the second test of scenario 10 and the maximum error rate was 9.945% in the second test of scenario 1. However, the average error rate for all scenarios was within 3%. It was determined that the representative cause of the maximum error occurred in the dual camera installed in the test vehicle. There were problems such as shaking caused by road surface vibration and air resistance during driving, changes in ambient brightness, and the process of focusing the video. Accordingly, it was determined that the result of calculating the distance to the preceding vehicle in the image where the problem occurred was incorrect. In the development stage of ADAS such as ACC, it is judged that only dual cameras can reduce the cost burden according to the above derivation of test results.

• Archives of Plastic Surgery
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• 제50권5호
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• pp.446-451
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• 2023

Background Elderly patients often have complications of blepharoptosis surgery that can result in the appearance or exacerbation of superficial punctate keratopathy (SPK). However, postoperative changes to SPK status have not been previously reported. We used subjective assessment of symptoms and measurement of SPK scale classification to investigate the safety and efficacy of blepharoptosis surgery in elderly patients. Methods Included in this prospective study were 22 patients (44 eyes) with bilateral blepharoptosis that underwent surgery. Patients comprised 8 males and 14 females with a mean (±standard deviation) age of 75.7 ± 8.2 years (range: 61-89). Blepharoptosis surgery consisted of transcutaneous levator advancement and blepharoplasty including resection of soft tissue (skin, subcutaneous tissue, and the orbicularis oculi muscle). Margin reflex distance-1 (MRD-1) measurement, a questionnaire survey of symptoms and SPK scale classification, was administered preoperatively and 3 months postoperatively for evaluation. Results The median MRD-1 was 1 mm preoperatively and 2.5 mm postoperatively, representing a significant postoperative improvement. SPK area and density scores were found to increase when the MRD-1 increase was more than 2.5 mm with surgery. All 10 items on the questionnaire tended have increased scores after surgery, and significant differences were observed in 7 items (poor visibility, ocular fatigue, heavy eyelid, foreign body sensation, difficulty in focusing, headaches, and stiff shoulders). Conclusion Blepharoptosis surgery was found to be a safe and effective way to maintain the increase in MRD-1 within 2.0 mm. Despite the benefits, surgeons must nonetheless be aware that blepharoptosis surgery is a delicate procedure in elderly people.

• The Korean Journal of Physiology
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• 제9권2호
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• pp.7-15
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• 1975

The maximum breathing capacity (MBC) and the maximum mid-expiratory flow rate (MMF) are widely used in evaluation of the ventilatory function, among various parameters of pulmonary function. The MBC volume is the amount of gas which can be exchanged per unit time during maximal voluntary hyperventilation. Performance of this test, unlike that of single breath maneuvers, is affected by the integrity of the respiratory bellows as a whole including such factors are respiratory muscle blood supply, fatigue, and progressive trapping of air. Because of this, the MBC and its relation to ventilatory requirement correlates more closely with subjective dyspnea than does any other test. The MMF is the average flow rate during expiration of the middle 50% of the vital capacity. The MMF is a measurement of a fast vital capacity related to the time required for the maneuver and the MMF relates much better to other dynamic tests of ventilatory function and to dyspnea than total vital capacity, because the MMF reflects the effective volume, or gas per unit of time. Therefore, it is important to have a prediction formula with one can compute the normal value for the subject and the compare with the measured value. However, the formulas for prediction of both MBC and MMF of the Korean children and adolescents are not yet available in the present. Hence, present investigation was attempt to derive the formulas for prediction of both MBC and MMF of the Korean children and adolescents. MBC and MMF were measured in 1,037 healthy Korean children and adolescents (1,035 male and 1,002 female) whose ages ranged from 8 to 18 years. A spirometer (9L, Collins) was used for the measurement of MBC and MMF. Both MBC and MMF were measured 3times in a standing position and the highest values were used. For measurement, the $CO_2$ absorber and sadd valve were removed from the spirometer in order to reduce the resistance in the breathing circuit and the subject was asked to breathe as fast and deeply as possible for 12 seconds in MBC and to exhale completely as fast as possible after maximum inspiration for MMF. During the measurement, investigator stood by the subject to give a constant encouragement. All the measured values were subsequently converted to values at BTPS. The formulas for MBC and MMF were derived by a manner similar to those for Baldwin et al (1949) and Im (1965) as function of age and BSA or age and height. The prediction formulas for MBC (L/min, BTPS) and MMF (L/min, BTPS) of the Korean children and adolescents as derived in this investigation are as follows: For male, MBC=[41.70+{$2.69{\times}Age(years)$}]${\times}BSA$ $(m^{2})$ MBC=[0.083+{$0.045{\times}Age(years)$}]${\times}Ht$ (cm) For female, MBC=[45.53+{$1.55{\times}Age(years)$}]${\times}BSA$ $(m^2)$ MBC=[0.189+{$0.029{\times}Age(years)$}]${\times}Ht$ (cm) For male, MMF= [0.544+{$0.066{\times}Age(years)$}]${\times}Ht$ (cm) For female, MMF=[0.416+{$0.064{\times}Age(years)$}]${\times}Ht$ (cm)

• 대한인간공학회지
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• 제26권1호
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• pp.87-92
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• 2007

KTX (Korea Train eXpress) is launched as the $5^{th}$ develop a ride-comfort model for high-speed rail pasengers using structural equation model (SEM). Both qualitative and quantitative factors affecting ride-comfort were investigated, and employed to construct a comprehensive ride-comfort model. The SEM model was built with twenty measurement variables and seven latent variables for the evaluation of ride-comfort of high-speed train passenger. A total of six hundreds thirty two subjects participated in the evaluation using face-to-face survey method. As a result, the proposed SEM model model fitnes (GFI=0.93). According to the results, overall ride-comfort was significantly affected by the seat-, fatigue-, interior-related, and customer satisfaction variables such as fare. Among the engineering design variables of high-speed train, seat-related variables were identified as critical factors of the ride-comfort. It is expected that the result of this study could be useful for the enhancement of ride comfort in next generation KTX.

• Journal of Welding and Joining
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• 제30권6호
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• pp.74-79
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• 2012

It depends on the joint configuration, dimensions and constraints of the joint whether the residual stress at the root of single-sided butt weld is tensile or not. Therefore, recommendation is generally made that high R ratio should be used in the fatigue test of welded joint in order to prevent excessively long life caused by compressive residual stress. In this research, the residual stress profile in butt weld joint was obtained through compliance method, using successive extension of a slot and measurement of the variation of strain during the slot extension. The residual stress profile was firstly assumed to be the linear summation of Legendre polynomials up to 9th order excluding 0th and 1st order. Strain variation on the surface was measured while the slot was being extended by cutting to find out the 8 unknown coefficients of each polynomial term. The cut was made by the electric discharge machine. It was concluded that the residual stress near the surface is positive valued, however, it turned into the negative value as soon as it passed through 2 or 3 mm of the depth.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.181.2-181.2
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• 2016

OLED 소자는 발광 방향에 따라 Bottom Emission 방식과 Top Emission 방식으로 나뉜다. 이 중 대면적 OLED TV 적용에 개구율이 더 높은 Top Emission방식을 선호하는 추세이다. 높은 개구율을 가진 Top Emission OLED소자를 위해서는 투명하고 전도성이 높은 캐소드가 중요하다. 본 연구에서는 Themal Evaporation 시스템을 이용하여 증착한 $SnO_2/Ag-Pd-Cu(APC)/SnO_2$ hybrid 전극의 특성을 연구하고 Oxide/Metal/Oxide(OMO) hybrid 박막의 bending mechanism을 제시하였다. base pressure는 $1{\times}10^{-6}Torr$로 고정하고 $SnO_2$ 박막은 0.34A / 0.32V, APC 박막은 0.46A / 0.40V의 power로 성막하였다. APC와 $SnO_2$의 두께를 변수로 OMO 전극을 제작하였고 그 전기적, 광학적 특성을 Hall measurement, UV/Visible spectroscopy을 이용하여 분석하고 Figure of merit 값을 바탕으로 최적 두께를 설정하였다. UPS(Ultraviolet Photoelectron Spectroscopy) 분석으로 $SnO_2/APC/SnO_2$ 전극의 일함수을 통해 투명 cathode로 쓰였을 때 $SnO_2$ 층이 buffer layer역할을 함을 확인하였다. XPS(X-ray photoelectron spectroscopy)를 이용하여 정성분석과 정량분석을 하였고 OMO hybrid 전극의 bending mechanism 연구를 위해 다양한 bending test (Inner/Outer dynamic fatigue test, twisting test, rolling test)를 진행하였다. 물리적 힘이 가해진 OMO hybrid 전극의 표면과 구조는 FE-SEM(Field Emission Scanning Electron Microscope) 분석을 통해서 확인할 수 있었다.

• 한국자동차공학회논문집
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• 제9권1호
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• pp.198-204
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• 2001

The shot peening is largely used for a surface treatment of metallic components where small spherical pellets called shots are blasted onto the surface with velocities up to 100 m/s. This treatment leads to improvement of fatigue behavior due to the developed compressive residual stresses, and so it has gained widespread acceptance I the automobile and aerospace industries. The residual stress profile on surface layer depends on the parameters of shot peening, which are, shot velocity, shot diameter, coverage, impact angle, material properties etc. and the method to confirm this profile is the measurement by X-ray diffractometer only. Despite the importance to automobile ad aerospace industries, little attention has been devoted to the accurate modelling of the process. In this paper, the simulation technique is applied to predict the magnitude ad distribution of the residual stress and plastic deformation caused by shot peening with the help of the finite element analysis.

• 한국환경과학회지
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• 제22권4호
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• pp.435-442
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• 2013

The purpose of this study, the type of rooftop learn more about the psychological benefits to users has been carried out, and healthy college students were examined in 40 patients. Conduct research to make the rooftop of the type of lawn, trees, ecological garden, wetland biotope, flowering plant in Seoul were divided into six groups. Measurement methods based on the type designation of the Planting and landscape photography by once the participants for each 10 minutes to watch and mood state tests (POMS) and the mean fractionation (SD), based on survey information about the psychological effects were correlated. Mood States test lawn, tree-oriented type, flowering plant stability in type, kindness, openness, and the effect of raising warme there was a tension, anxiety, depression, anger inhibition was effective. In contrast, depression and fatigue are common rooftop greening, respectively. The results in terms of the psychological effects of the type of rooftop garden ecology and wetland biotope than lawn, tree-oriented type, flowering plant types of users with a positive psychological effect seemed to be better.

• 한국전자통신학회논문지
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• 제13권3호
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• pp.677-684
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• 2018

최근 운전 도중 운전자가 가지는 부정적인 감정 상태로 인한 문제점이 커지고 있으며 특히 우리나라 포함 교통이 혼잡한 나라에서는 교통사고뿐만 아니라 소위 '분노 운전'이라는 범죄 행위로 이어지는 사례가 잦아지고 있다. 이와 같은 상황에서 무선 통신 및 웨어러블 기술을 활용하여 스트레스나 피로로 인한 운전자의 감정 상태를 측정할 수 있다면 매우 유용할 수 있다. 본 연구는 운전자의 다양한 생체 신호를 측정 및 관찰할 수 있는 시스템을 구현하고 측정 결과 분석을 통하여 운전자의 감정 상태를 판단하고 관찰하며 예측된 운전자의 감정 상태에 대한 신뢰성을 높이기 위한 것이다. 본 논문에서는 이 연구의 전반부로서 현재 개발이 완료된 시스템 구현 과정과 실험 방법에 대해서 소개하고자 한다.

• Journal of Mechanical Science and Technology
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• 제18권6호
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• pp.961-971
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• 2004

Methods for determination of the crack opening stress intensity factor ($K_{op}$) and for estimation of the effective stress intensity factor range ($\Delta{K}_{eff}$) are evaluated for crack growth test data of aluminum alloys. Three methods of determining $K_{op}$, visual measurement, ASTM offset compliance method, and the neural network method proposed by Kang and Song, and three methods of estimating $\Delta{K}_{eff}$, conventional, the 2/PIO and 2/PI methods proposed by Donald and Paris, are compared in a quantitative manner by using evaluation criteria. For all $K_{op}$ determination methods discussed, the 2/PI method of estimating $\Delta{K}_{eff}$ provides good results. The neural network method of determining $K_{op}$ provides good correlation of crack growth data. It is recommended to use 2/PI estimation with the neural $K_{op}$ determination method. The ASTM offset method used in conjunction with 2/PI estimation shows a possibility of successful application. It is desired to improve the ASTM method.