운전면허시험 강화에 따른 교통안전 효과 분석 연구

이창민,이철기,이상수,윤일수,Lee, Chang Min,Lee, Choul Ki,Lee, Sang Soo,Yun, Ilsoo 한국ITS학회 2020 한국ITS학회논문지 Vol.19 No.5

2011년 운전면허시험 간소화 제도가 도입된 이후 변별력이 없어 교통안전에 미흡하다는 부정적인 견해가 많았다. 이에 2016년 12월 22일부터 개선된 운전면허시험이 도입되었고 현재까지 운영되고 있다. 따라서 본 연구는 개선된 운전면허시험이 도입된 이후 어떤 효과가 있었으며 무엇이 유효했는지 살펴보고자 교통안전 통계자료 분석, 체감도 조사를 수행하였다. 분석 결과, 현재 시험이 적정한 변별력을 갖췄다고 보여 지며, 과거보다 공정성 체감은 상당 수준 올라온 것으로 인식된다. 실효성 부문에서는 아직까지 운전자의 눈높이를 만족하지 못한 것으로 사료되며, 향후에는 보다 심도 있는 연구와 교통선진국 사례를 검토할 필요가 있다. After the driver test was simplified in 2011, there were criticisms of its inadequate level of safety standards. A new and improved test was adopted in December 2016. This study investigated the impact of the changes to the test on safety, and analyzed traffic safety statistics and sensory evaluations to determine the effect of the improved driving license test. The analysis concluded that the current test has a proper discrimination and that fairness has increased considerably. The analysis also identified measures that, once adopted, will improve the conduct of driver tests. In the future, it will be necessary to conduct more in-depth studies and to review cases of advanced countries.

PSS 상 버퍼층 종류에 따른 GaN 박막 성장 특성 비교

이창민,강병훈,김대식,변동진,Lee, Chang-Min,Kang, Byung Hoon,Kim, Dae-Sik,Byun, Dongjin 한국재료학회 2014 한국재료학회지 Vol.24 No.12

GaN is most commonly used to make LED elements. But, due to differences of the thermal expansion coefficient and lattice mismatch with sapphire, dislocations have occurred at about $109{\sim}1010/cm^2$. Generally, a low temperature GaN buffer layer is used between the GaN layer and the sapphire substrate in order to reduce the dislocation density and improve the characteristics of the thin film, and thus to increase the efficiency of the LED. Further, patterned sapphire substrate (PSS) are applied to improve the light extraction efficiency. In this experiment, using an AlN buffer layer on PSS in place of the GaN buffer layer that is used mainly to improve the properties of the GaN film, light extraction efficiency and overall properties of the thin film are improved at the same time. The AlN buffer layer was deposited by using a sputter and the AlN buffer layer thickness was determined to be 25 nm through XRD analysis after growing the GaN film at $1070^{\circ}C$ on the AlN buffer CPSS (C-plane Patterned Sapphire Substrate, AlN buffer 25 nm, 100 nm, 200 nm, 300 nm). The GaN film layer formed by applying a 2 step epitaxial lateral overgrowth (ELOG) process, and by changing temperatures ($1020{\sim}1070^{\circ}C$) and pressures (85~300 Torr). To confirm the surface morphology, we used SEM, AFM, and optical microscopy. To analyze the properties (dislocation density and crystallinity) of a thin film, we used HR-XRD and Cathodoluminescence.

아연계 고온건식 탈황제의 제조 및 반응특성연구

이창민,신상백,김성현 ( C . M . Lee,S . B . Shin,S . H . Kim ) 한국공업화학회 1997 응용화학 Vol.1 No.1

N/A

Analog용 PIN-Photodiode의 광 패키징 기술 및 특성 연구

이창민,권기영,Lee Chang Min,Kwon Kee Young 대한전자공학회 2005 電子工學會論文誌-SD (Semiconductor and devices) Vol.42 No.3

본 논문에서는 단일모드 광섬유를 부착한 analog용 PIN-Photodiode를 제작하고 소자의 특성을 분석하였다. 제작된 analog 용 PIN-photodiode의 대역폭은 1.5 GHz이였으며, 암전류는 20 pA이고, 정전용량은 0.48 pF이였으며, 응답도(responsivity)는 0.9 V/W 이고, 2차 상호변조(IM2, second order distortion)는 -72 dBc이였다. 본 논문에서는 응답도와 IM2 특성을 실시간으로 모니터링하며 정렬하는 새로운 광 패키징 기술을 개발하였다. 그 결과 응답도는 0.03 V/W 향상되었으며, IM2는 $3\~5dBc$ 향상 되었고, 부적합 발생률도 $3.5\%$ 감소하였다. We fabricated PIN-Photodiodes with a single mode fiber for analog communications and analyzed characteristics of the devices. The fabricated PIN-Photodiode shows a bandwidth of 1.5 GHz, a dark current of 20 p4 a capacitance of 0.48 pF, and the responsivity of 0.9 V/W, a second order distortion of -72 dBc. In this paper, we developed a new optical Packaging technology that is aligning in real-time monitoring of both responsivity and IM2 characteristics. As a result responsivity has been improved by 0.03 V/W, and also U has been improved by $3\~5\;dBc$. On the other hand, failure ratio has been reduced by $3.5\%$.

구두 굽의 형태가 인체의 근골격계에 미치는 영향에 관한 연구

이창민,정은희,Lee, Chang-Min,Jeong, Eun-Hui 대한인간공학회 2004 大韓人間工學會誌 Vol.23 No.1

In terms of women engaged in clerical job. working time of the workers who mainly keep standing with their high-heeled shoes on has been increasing. According]y. they are exposed to many kinds of foot deformation caused by loads of lower back and lower extremities due to high-heeled shoes. The type of heels they usually wear are diverse though the hight is same. In this study. we investigated most women's favorite styles of shoes concerned with heights. types and contact areas of the heels. Hence. we designed three kinds of shoes for an experiment: their contact areas with ground are 1 cm2. 2-4 cm2 and over 9 cm2 according to the heel heights. respectively. To investigate the biomechanical effects. analysis of motion and EMG were applied to the experiments. In addition. foot pressure distribution was measured for more detailed analysis. Six healthy young women were participated in this experiments. The result showed the heel becoming higher and narrower increased not only fluctuation of CBM(Center of Body Mass). but also the load of low back muscle and lower extremities. Accordingly. there was significant difference among types of the heel in terms of the role supporting load of the body. though the height is same. Especially. the difference among the pressures on a foot was most significant. In conclusion. we verified biomechanical effects are related with the contact area of a heel with ground as well as the hight.

레이저 클래딩 공정 조건이 코발트 합금-텅스텐 카바이드 혼합 코팅층의 균열 발생에 미치는 영향

이창민,박형권,이창희,Lee, Changmin,Park, Hyungkwon,Lee, Changhee 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.6

In this study, cracking susceptibility of laser cladding was investigated according to the processing parameters such as laser power, scan speed and feeding rate with blended powders of stellite#6 and technolase40s (WC+NiCr). The solidification microstructure of clad was composed of Co-based dendrite structures with ${\gamma}+Cr7C3$ eutectic phases at the dendritic boundaries. The crack propagation showed transgranular fracture along dendritic boundaries due to brittle chrome carbide at the eutectic phases. From results of fractography experiments, the fracture surface was typical cleavage brittle fracture in the clad and substrate. The number of clad cracks, caused by a tensile stress after the solidification, increased with increase of laser power, scan speed and feeding rate. Increase of the laser power caused large pores by facilitating WC decarburizing reaction. And the pores affected increase of crack susceptibility. High scan speed caused increment of clad cracks due to thermal stress and WC particle fractures. Also, increase of the feeding rate accompanied an amount of WC particles causing crack initiation and decarburizing reaction.

다탄성 Insole의 Workload 감소 효과에 관한 연구

이창민,이경득,오연주,김진훈,Lee, Chang-Min,Lee, Kyun-Deuk,Oh, Yeon-Ju,Kim, Jin-Hoon 대한인간공학회 2007 大韓人間工學會誌 Vol.26 No.2

The Work-Related Musculoskeletal Disorders (WMSDs) can be occurred by various factors such as repetition, forceful exertions and awkward postures. Especially, occurrences of the WMSDs on the waist and lower limb are reported in workplaces, demanded standing postures for a long time, in service and manufacturing industry. The static and standing postures without movement for a long time increase work loads to the lower limb and the waist. Accordingly, anti-fatigue mat or anti-fatigue insole is used as a preventing device of the WMSDs. However anti-fatigue mats are limited in space and movement. In this study, multi-elastic insoles are designed and shown the effects of the workload reduction for a long time under the standing work. The foot pressures and EMG (Electromyography) are measured at 0 hour and after 2 hours by 6 health students in their twenties. The 6 prototype insoles are designed with three elastic (Low, Medium and High). These insoles are compared with no insole (insole type 7) as control group. The EMG measurement was conducted to waist (erector spinae muscle), thigh (vastus lateralis muscle) and calf (gastrocnemius muscle). The foot pressure is analyzed by mean pressure value and the EMG analysis is investigated through MF (Median Frequency), MPF (Mean Power Frequency) and ZCR (Zero Crossing Rate). The results of the foot pressure show that the multi-elastic insoles had smaller foot pressure value than that of no-insole. Moreover, Insole 2 and Insole 3 have the smallest increasing rate in foot pressure. The EMG results show that the multi-elastic insoles had smaller EMG shift value than that of no-insole in 2 hour, and then shift value shows the smallest value in Insole 2. Therefore, this study presents that the multi-elastic insoles have reducing effects of the work load for a long time standing work in both side of foot pressure and EMG.

망막질환이 동반된 난치성 녹내장에서의 유리체절제술과 평면부를 통한 아메드장치삽입술

이창민,김은아,조영욱,Chang Min Lee,Eun Ah Kim,Young Wook Cho 대한안과학회 2011 대한안과학회지 Vol.52 No.1

Purpose: To evaluate the efficacy and long-term prognosis of pars plana vitrectomy and Ahmed valve implantation for intractable glaucoma comorbid with retinal disorders. Methods: A retrospective review of 34 eyes of 30 patients receiving pars plana vitrectomy and Ahmed valve implantation for intractable glaucoma comorbid with retinal disorders was performed. Preoperative and postoperative intraocular pressure (IOP) and visual acuity, the usage of IOP-lowering medications and postoperative complications, and surgical success rate were evaluated. Results: IOP and the number of IOP-lowering medications showed a significant decrease after pars plana vitrectomy and Ahmed valve implantation, as compared to before surgery (p < 0.001). The success rate was 88%, 88%, 84% and 85% postoperatively at 1 month, 6 months, 1 year and 3 years respectively. The mean follow up period was 24.21 ± 14.99 months. Complications related to surgery included hyphema in 2 eyes, recurrent corneal epithelial erosion and defect in 2 eyes, corneal ulcer in 2 eyes and vitreous hemorrhage in 4 eyes. Visual acuity improved in 14 eyes (41.1%), no changes in 13 eyes (38.2%) and decreased in 7 eyes (20.6%). Conclusions: Pars plana vitrectomy and Ahmed valve implantation for intractable glaucoma comorbid with retinal disorders show long-term efficacy in lowering IOP. J Korean Ophthalmol Soc 2011;52(1):46-52

집배원 근골격계 질환 예방을 위한 수구분대 개선에 관한 연구

이창민,오연주,Lee, Chang-Min,O, Yeon-Ju 대한인간공학회 2004 大韓人間工學會誌 Vol.23 No.4

The purpose of this study is to redesign a letter sorting station and to present the optimal work-space through the ergonomic analysis of the sorting station for reducing the 'Work-Related MusculoSkeletal Disorders(WMSDs)'. We surveyed the work environment in terms of the reason causing WMSDs. According to the survey results, Deltoid on the arm, Trapezius on the shoulder and Erector Spinae on the waist are most frequent attacking parts. Accordingly, We classified sorting stations by the horizontal work-space(Level 1, Level 2, Level 3) and the vertical work space(Level 1, Level 2) based on the criteria of ergonomic optimal work-space. In addition we improved the sorting station through investigation and analysis of the work-load regard the each defined work-space. In order to analyze the effect of the horizontal and vertical work-space, subjects carried out simulated sorting tasks. Each level(Level 1, Level 2, Level3) of the horizontal work-space is significant regarding each muscles(the shoulder, arm and waist), and each level(Level 1, Level 2) of the vertical work-space is significant regarding the arm and waist, but not shoulder. Finally, we founded the difference of work-load according to the work-spaces. Then, it is necessary to improve the work-space causing the high work-load(Level 3 of the horizontal work-space). Then, this study presented the specification of a sorting station which is suitable to the korean body size, and constructed the 3D shaped model of the stations by the ergonomic analysis.

도시 물 문제 저감을 위한 회복탄력적 사회기반시설 구축: 1. 도시 홍수 문제 구조적 대안의 내구성 평가

이창민,정지현,안진성,김재영,최용주,Lee, Changmin,Jung, Jihyeun,An, Jinsung,Kim, Jae Young,Choi, Yongju 응용생태공학회 2016 Ecology and resilient infrastructure Vol.3 No.2

도시 내 인구집중과 기후변화로 인해 다양한 형태의 도시 물 문제가 발생한다. 이에 대한 피해 예방과 사회적 손실 최소화를 위해 회복탄력적인 대안 수립이 필요하다. 본 연구는 도시 물 문제 저감을 위한 회복탄력적 사회기반시설 구축 전략 수립에 관한 기초연구로서, 대표적인 도시 물 문제 중 하나인 도시홍수를 사례로 하여 구조적 대안의 내구성을 평가하였다. 내구성 평가를 위한 지표로 내구성 지수 (robustness index, RI) 및 비용지수 (cost index, CI)를 결합한 내구성-비용지수 (robustness cost index, RCI)를 제안하고, 이를 강남역 상습침수구역에 적용하여 기존 기반시설과 구조적 대안 (하수관거 확충, 저류조 설치, 옥상녹화)을 평가하였다. 그 결과, 2~20년 빈도의 강우강도범위에서 저류조와 옥상녹화설치가 상대적으로 높은 RCI 값을 나타내었고 두 대안 중 RCI가 보다 높은 대안은 강우강도에 따라 달라지는 경향을 보였다. 30년 빈도 강우강도에 대하여는 저류조와 옥상녹화를 병용 설치하는 대안이 가장 높은 RCI 값을 나타내어 가장 회복탄력적인 대안으로 확인되었다. 최종적으로 재해의 계획규모에 따른 현행 사회기반시설의 내구성 평가 및 최적의 구조적 대안 선택 절차를 수립하여, 도시홍수 문제에 대한 회복탄력적 사회기반시설 구축 전략을 제시하였다. Current cities encounter various types of water problems due to rapid urbanization and climate change. The increasing significance of urban water problems calls for the establishment of resilient alternatives to prevent and minimize social loss that results from these phenomena. As a background research for establishing resilient infrastructures for the mitigation of urban water problems, we evaluated the robustness of structural alternatives for urban flood as a representative case. Combining the robustness index (RI) and the cost index (CI), we suggested the robustness-cost index (RCI) as an indicator of the robustness of structural alternatives, and applied the index to assess the existing infrastructures and structural alternatives (i.e., sewer network expansion, additional storage tank construction, and green roof construction) at a site prone to floods located around Gangnam-station, Seoul, Korea. At a rainfall intensity frequency range of 2 to 20 years, the usage of a storage tank and a green roof showed relatively high RCI value, with a variation of an alternative showing greater RCI between the two depending on the size of design rainfall. For a rainfall intensity frequency of 30 years, installing a storage tank with some green roofing was the most resilient alternative based on the RCI value. We proposed strategies for establishing resilient infrastructures for the mitigation of urban floods by evaluating the robustness of existing infrastructures and selecting optimal structural alternatives with the consideration of scales of design disaster.