Safety Analysis of Roundabout Designs based on Geometric and Speed Characteristics

김상엽,최재성 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.6

The study investigates data concerning crashes at roundabouts in order to identify the major factors influencing such events in South Korea. In this investigation, three stages of research tasks were carried out. First, crashes which occurred at South Korean roundabouts were categorized and subsequently compared with international cases. Second, field surveys were conducted in order to investigate how vehicle speeds influence the occurrence of accidents. Third, a statistical analysis was performed in order to investigate the correlation between roundabout geometry and crash occurrences and to reveal major geometric elements of roundabout safety. It was revealed in the study that most vehicles slow down substantially around roundabouts and recover their speed after the roundabouts. Based on the statistical analysis, it was found that negative binomial distribution would give a better performance. In addition, in contrast to cases in the US, the final selection of the independent variables includes as follows: the number of approaches, the number of entering lanes, the entry width, the flare width, the number of circulating lanes and the circulating lane width. Finally, the study provided a model with which to capture the relationship between geometric design elements and the occurrence of crashes at roundabouts. It is anticipated that this model will be applied by engineers to better predict crash occurrences at roundabouts.

Cutaneous Melanoma in Asians

김상엽,윤숙정 전남대학교 의과학연구소 2016 전남의대학술지 Vol.52 No.3

Malignant melanoma is a rare disease in Asians but potentially the most aggressive form of skin cancer worldwide. It can occur in any melanocyte-containing anatomic site. Four main cutaneous melanoma subtypes are recognized: lentigo maligna melanoma, superficial spreading melanoma, acral lentiginous melanoma (ALM), and nodular melanoma. Generally, excessive exposure to ultraviolet (UV) radiation increases the risk of melanoma. The exception is ALM, which is the most common melanoma subtype in Asians and is not associated with UV radiation. ALM presents as dark brownish to black, irregular maculopatches, nodules, or ulcers on the palms, soles, and nails. The lesions may be misdiagnosed as more benign lesions, such as warts, ulcers, hematomas, foreign bodies, or fungal infections, especially in amelanotic acral melanomas where black pigments are absent. The aim of this brief review is to improve understanding and the rate of early detection thereby reducing mortality, especially regarding cutaneous melanoma in Asians.

하지의 닫힌 사슬 운동시 대퇴부 테이핑 적용이 등속성 근기능에 미치는 영향

김상엽,윤영제,최원제,Kim, Sang-Yeup,Yoon, Young-Ieoi,Choi, Won-Jye 대한고유수용성신경근촉진법학회 2010 PNF and Movement Vol.8 No.3

Purpose : The purpose of this study was to investigate effects of kinesio taping of thigh muscle on isokinetic muscular function during closed kinetic chain exercise of lower extremity. Methods : Twenty healthy males were participated in this study. The isokinetic muscular function of closed kinetic chain were measured for peak torque, peak torque % body weight, average power, max rep tot work before and after application of kinesio taping on thigh muscles. Results : At $60^{\circ}/s$ peak force and peak force % body weight were significant increased in both extension(p<0.01) and flexion(p<0.001) after applying kinesio taping. At $180^{\circ}/s$ average power was significant increased in both extension and flexion after applying taping(p<0.001). At $240^{\circ}/s$ max rep tot work was significant increased in both extension(p<0.001) and flexion(p<0.05). Conclusion : This study suggests that application of kinesio taping on thigh muscle was more effective to improve isokinetic muscular function in closed kinetic chain exercise of lower extremity.

폴리실리콘 기판 위에 형성된 코발트 니켈 복합실리사이드 박막의 열처리 온도에 따른 물성과 미세구조변화

김상엽,송오성,Kim, Sang-Yeob,Song, Oh-Sung 한국재료학회 2006 한국재료학회지 Vol.16 No.9

Silicides have been required to be below 40 nm-thick and to have low contact resistance without agglomeration at high silicidation temperature. We fabricated composite silicide layers on the wafers from Ni(20 nm)/Co(20 nm)/poly-Si(70 nm) structure by rapid thermal annealing of $700{\sim}1100^{\circ}C$ for 40 seconds. The sheet resistance, surface composition, cross-sectional microstructure, and surface roughness were investigated by a four point probe, a X-ray diffractometer, an Auger electron spectroscopy, a field emission scanning electron microscope, and a scanning probe microscope, respectively. The sheet resistance increased abruptly while thickness decreased as silicidation temperature increased. We propose that the fast metal diffusion along the silicon grain boundary lead to the poly silicon mixing and inversion. Our results imply that we may consider the serious thermal instability in designing and process for the sub-0.1 um CMOS devices.

Stream Data Analysis of the Weather on the Location using Principal Component Analysis

김상엽,김광덕,배경호,류근호 한국측량학회 2010 한국측량학회지 Vol.28 No.2

The recent advance of sensor networks and ubiquitous techniques allow collecting and analyzing of the data which overcome the limitation imposed by time and space in real-time for making decisions. Also, analysis and prediction of collected data can support useful and necessary information to users. The collected data in sensor networks environment is the stream data which has continuous, unlimited and sequential properties. Because of the continuous, unlimited and large volume properties of stream data, managing stream data is difficult. And the stream data needs dynamic processing method because of the memory constraint and access limitation. Accordingly, we analyze correlation stream data using principal component analysis. And using result of analysis, it helps users for making decisions.

인공호흡기 치료와 관련된 폐간질기종 발생의 위험인자에 대한 연구

김상엽,이필상,이상길 대한소아청소년과학회 2008 Clinical and Experimental Pediatrics (CEP) Vol.51 No.11

Purpose:Pulmonary interstitial emphysema (PIE) primarily occurs in preterm infants suffering from respiratory distress syndrome (RDS) and kept under mechanical ventilator care. Therefore, this study aimed to examine various risk factors for PIE, to identify conditions that can decrease the possibility of PIE development. Methods:PIE classification was conducted for 183 patients diagnosed to have RDS and receiving mechanical ventilator care with pulmonary surfactant between March 2000 and February 2007. The characteristics of each patient were analyzed through retrospective examination of their medical histories. Results:Among 183 patients, 17 had PIE; all factors, including birth weight, gestational age, RDS grade III or above, chorioamnionitis, and premature rupture of membranes, were statistically significant (P<0.05). The period of mechanical ventilator use was statistically significant, but the peak mean airway pressure and peak partial pressure of inspired oxygen were not. PIE mainly occurred on the right side or both sides rather than the left side and mostly developed within 72 h. The PIE group showed higher mortality rate than the control group, and the major cause of mortality was pneumothorax. Conclusion:Risk factors for PIE in infants suffering from RDS and kept under mechanical ventilator care include low gestational age, low birth weight, chorioamnionitis, and premature rupture of membranes. If any risk factors are noted, the infant must be observed closely for at least 72 h after birth. (Korean J Pediatr 2008;51:1179-1184) Purpose:Pulmonary interstitial emphysema (PIE) primarily occurs in preterm infants suffering from respiratory distress syndrome (RDS) and kept under mechanical ventilator care. Therefore, this study aimed to examine various risk factors for PIE, to identify conditions that can decrease the possibility of PIE development. Methods:PIE classification was conducted for 183 patients diagnosed to have RDS and receiving mechanical ventilator care with pulmonary surfactant between March 2000 and February 2007. The characteristics of each patient were analyzed through retrospective examination of their medical histories. Results:Among 183 patients, 17 had PIE; all factors, including birth weight, gestational age, RDS grade III or above, chorioamnionitis, and premature rupture of membranes, were statistically significant (P<0.05). The period of mechanical ventilator use was statistically significant, but the peak mean airway pressure and peak partial pressure of inspired oxygen were not. PIE mainly occurred on the right side or both sides rather than the left side and mostly developed within 72 h. The PIE group showed higher mortality rate than the control group, and the major cause of mortality was pneumothorax. Conclusion:Risk factors for PIE in infants suffering from RDS and kept under mechanical ventilator care include low gestational age, low birth weight, chorioamnionitis, and premature rupture of membranes. If any risk factors are noted, the infant must be observed closely for at least 72 h after birth. (Korean J Pediatr 2008;51:1179-1184)

선형유형 구분을 통한 고속도로 사고빈도모형 개발 연구

김상엽,최재성,이수범,김성민,조원범,김용석 한국도로학회 2011 한국도로학회논문집 Vol.13 No.1

This paper presents how one can investigate the effects on crash occurrence of freeway geometric design elements including the horizontal,vertical alignment and road environment. At present, the available research results for the most part involve geometric data analysis that are obtained along a relatively long section of freeway, and, because of the long section′s diverse geometric conditions, the results tend to miss the specific local geometric impacts on vehicle crashes. In this regard, this research attempts to establish vehicle crash models based on a set of freeway geometric patterns whose crash generating characteristics are identical because they are homogeneous in terms of producing the same vehicle operating speeds,and subsequently their actual relationships are described by providing statistical analysis made in this research. Also each standard is comprised of part of straight, curve and continuous curve. This research has revealed that each type of model has different relation between accident and geometry structure. This research results should be useful for doing more reasonable highway designs and safety audit analysis. 본 연구에서는 고속도로를 대상으로 각각의 구간에 대한 선형유형을 구분하여 사고빈도모형을 개발하였다. 현재 사고빈도모형 부문의 연구는 주로 고속도로 구간 전체를 대상으로 한 연구가 대부분이기 때문에 거시적인 측면에서 사고빈도모형이 개발되었다고 할수 있으며, 이에 따라 각각의 구간특성이 정확히 반영되지 않은 상태에서의 사고빈도를 예측하였다고 볼 수 있다. 본 연구에서는 이러한 문제점을 인식하여, 동질구간 분할법을 사용하여 고속도로의 평면선형을 직선부, 곡선부, 연속곡선부로 구분하였고, 이를 군집분석을 통하여 직선부와 곡선부의 유형을 구분하여 고속도로의 각각의 구간별 특성을 반영한 사고빈도모형을 구축하였다. 본 연구 결과는 고속도로 각 구간의 사고빈도를 예측하는데 있어 더 정확하고 합리적인 결과를 도출해 낼 것이라 판단한다.

Determining the Sidewalk Pavement Width by Using Pedestrian Discomfort Levels and Movement Characteristics

김상엽,최재성,김용석 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.5

This paper presents a sidewalk pavement width design method for making more pedestrian friendly and walk-inspiring sidewalk pavements in the urban area. Instead of using the current sidewalk pavement width design standard that usually leads to having minimum values, this research investigated pedestrians’ preferences on the levels of service, surveyed actual foot path trajectories in the sidewalk pavements, and observed pedestrian movement characteristics in the streets. Further, these investigation results were summarized to propose a new urban sidewalk pavement width determination procedure. The proposed procedure was applied in a case study site in Seoul, and its application resulted in a much higher pedestrian level of service. It is anticipated that the proposed method should be of service in both planning and retrofitting urban streets to make more pedestrian sensitive street designs.

볼록형 최적화기법을 이용한 LQ-서보 설계 방법 (II) 시간 영역에서의 접근

김상엽,서병설 한국통신학회 2000 韓國通信學會論文誌 Vol.25 No.6

This paper concerns a development of LQ-servo PI controller design on the basis of time-domain approach. The motivation is because the previous design techniques developed on the frequency-domain is not well suited meet the time-domain design specifications. Our development techniques used in this paper is base on the convex optimization methods including Lagrange multiplier, dual concept, semidefinite programming. 본 논문은 시간 영역에서의 접근 방법에 기초하여 LQ-서보형 PI 제어기 설계 기법을 개발하였다. 이러한 연구의 동기가 된것은 주파수 영역에서 개발된 기존의 방법이 시간영역의 설계사양들을 잘 만족하지 않기 때문이다. 본 논문에서 개발된 기법은 라그랑지 곱셈기, 쌍대개념, 반한정 프로그래밍을 포함하는 볼록형최적화 기법에 기반을 둔다.

단계별 유산소성 운동이 근력발현에 미치는 영향

김상엽 한국스포츠리서치 2006 한국 스포츠 리서치 Vol.17 No.4