해외잡지동향

강상훈,Gang, Sang-Hun 대한건축사협회 2007 建築士 Vol.2007 No.4

Al/Cu 레이저 용접에서 spectrometer를 이용한 용접성 예측

강상훈,강민정,장용훈,김철희 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.11

세계적으로 온실가스를 줄이는 환경규제에 맞추기 위해 자동차 생산기업들은 전기자동차 생산량을 확대하고 있다. 전기차 생산량 증가에 맞추어 전기차의 핵심 부품인 배터리 생산목표량도 증가하고 있기 때문에, 자동화가 쉽고 빠른 공정속도 달성이 가능하며 소모품이 발생하지 않는 레이저 용접의 적용이 점차 확장되고 있다. 배터리의 특성상 배터리 용접부에는 전기 저항이 낮은 Al 및 Cu의 소재를 많이 사용한다. Al 및 Cu는 기존 산업 현장에서 많이 사용되고 있는 IR 레이저를 이용하면, 빔 흡수율이 낮아 레이저 용접 중 생성되는 키홀이 불안정하고 이로 인해 안정적인 용접이 어렵다. 따라서 Al 및 Cu를 이용한 배터리의 레이저 용접부는 지속적인 품질검사가 필수 불가결한 상황이다. 본 연구에서는 Al 1050, C1100의 소재를 겹치어 레이저 용접을 수행하였으며, 이 때 알루미늄은 상판에 배치하였다. 레이저 용접공정 중 품질 정보를 수집하기 위해 레이저 헤드에 동축으로 spectrometer를 설치하였으며, 공정 중 발생하는 다양한 파장대역의 세기를 측정하였다. 파장은 100 nm 범위별로 나누어 용접부 품질의 분석에 활용하였다.

휠체어기반 척수마비 환자 보조로봇 KARESII(KAIST Rehabilitation Engineereing Service System II)의 개발 경험 공유 -로봇팔을 중심으로

강상훈 한국로봇학회 2020 로봇과 인간 Vol.17 No.1

Effects of component geometries and inflow conditions on ejector operational mode

강상훈,김재강,남궁혁준 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10

The ejector system is a useful device for creating high altitude conditions for ground tests of supersonic engines. The ejector performance can be immediately changed by varying the ejector operational mode. The ejector nozzle pressure ratio is well known to have a significant effect of the operational mode of an ejector. However, the effects of the mixing duct length and other geometric design parameters on the ejector mode change have not been clearly determined. In this study, the effects of ejector component geometries and inflow conditions on ejector operational mode are investigated by numerical analysis. By changing the inflow conditions and geometric parameters, twelve test cases are studied. Using the numerical test results, the flow pattern and suction pressure performance of the ejector with a fixed secondary mass flow rate are compared. In the numerical test results, a high primary nozzle stagnation pressure induces a highly underexpanded flow, resulting in the critical operational mode. For the critical operational mode, the mixing duct must be sufficiently long to accommodate the shock train and the choking zone. Primary nozzles with wide angles also induce widely expanded nozzle flows and result in the critical operational mode.

하악 제3대구치 발치를 위한 예방적 항생제의 효용성

강상훈,김정인,박원서,이충국,이상휘,Kang, Sang-Hoon,Kim, Jung-In,Park, Won-Se,Yi, Choong-Kook,Lee, Sang-Hwy 대한구강악안면외과학회 2008 대한구강악안면외과학회지 Vol.34 No.3

This study analyzed the incidence of wound infection after the operation of mandibular third molar extraction in relation with antibiotic prophylaxis with the object of young and healthy patients. The study object was 1,177 mandibular third molars of 850 men of 20 to 25 years old without any specific systemic disease. Three methods of preventive antibiotic medication were selected according to the preventive antibiotic medication previously reported; three experimental groups were selected based on them, and the antibiotic used was amoxicillin($^{(R)}Kymoxin$, Yuhanyanghaeng, Seoul). The group 1 includes the patients that took the antibiotic orally before the operation(one hour earlier, 500mg) and for three days after the operation(250mg per time, three times/day), the group 2 is the ones that took the same antibiotic orally only once about one hour before the operation(500mg), and the group 3 did not take any antibiotics before and after the operation. And to compare the difficulties and the degrees of extraction during operations which can be possibly related to the wound infection after the operations, the mandibular third molars' impacted depths and extraction methods were investigated as well. To check if the wound was infected, observations with an internal of one week were performed twice after the operation, and the meaningfulness of the infection incidence was verified through Chi-square test using SPSS program(SPSS Inc., IL, USA). There was no statistically significant difference between the antibiotic medication methods and the wound infection incidence after the operation among the experimental groups. As examining the relations between the mandibular third molar operation methods and the wound infection incidence after the operation, there existed a statistically meaningful difference in the infection incidence according to the operation methods(p=0.020). And there was no statistically significant difference in the wound infection incidence according to the impacted depth of the mandibular third molar. Therefore, it is thought that there exists little necessity of prophylatic antibiotics medication when extracting the mandibular third molar of young and healthy men without any systemic disease in general; however, in case when it is expected that the possibility of infection will be high or the wound on the tissue will be severe, it is sure that the prophylactic antibiotics medication will be necessary.

The effect of Fe2+ state in electrical property variations of Sn-doped Hematite powders

강상훈,박성균,류수열,김수도,이윤정,윤성민,조환규,우균,조성진 American Ceramic Society 2017 Journal of the American Ceramic Society Vol.1 No.1

The Impact of Global Volatility on Asian Financial Markets

강상훈,최기홍,윤성민 한국자료분석학회 2014 Journal of the Korean Data Analysis Society Vol.16 No.4

This study investigated the intertemporal relationship between global volatility (VIX) and Asian financial markets. The VIX, aka "fear gauge," got a lot of attention during and after the financial crisis because it exploded when the markets crashed, and it tumbled as the markets rallied. In financial theory, there exists a positive expected returns and risk relationship. However, many empirical studies found a negative relationship between expected returns and implied volatility in financial markets. In this context, this study investigated the relationship between the implied volatility (VIX) and Asian financial markets. We considered the impact of VIX changes on financial markets (equity and foreign exchange markets). In doing it so, utilizing the VAR model, we examined the relationship between expected returns and volatility in Asian financial markets. We supposed that equity returns have a negative relationship with the VIX, but exchange rates have a positive relationship with the VIX. This evidence indicates that investors require more portfolio insurance premiums in the periods of high market turmoil.

Analyzing the Network Structure of Spillover Connectedness Across Index Futures Markets During Market Distress Periods

강상훈 한국파생상품학회 2019 선물연구 Vol.27 No.2

This paper aims to investigate the network structure of connectedness among global index futures markets in different distress periods. In this purpose, this employs the multivariate DECO-GARCH model of Engle and Kelly (2012) and the spillover index method of Diebold and Yilmaz (2014). From empirical analysis, this paper finds an evidence of a positive equicorrelation among global index futures, implying the contagion effect in global index futures markets. The spillover connectedness is intensified due to recent market distress, i.e., the 2008-2009 GFC, the 2010-2012 ESDC, the collapse of Chinese stock market in 2015, and the US FRB interest rate hike in 2018. Further, this paper measures the direction and strength of volatility connectedness assessed by the net pairwise directional spillover indexes. Thus this paper identifies the net spillover connectedness (transmitter/receiver) across global index futures markets. Finally, this paper shows the network structure of spillover connectedness in different market distress periods, and provides the channels of spillover connectedness across global index future markets.

Revisited Return and Volatility Spillover Effect in Korea

강상훈,윤성민 한국경제연구학회 2013 Korea and the World Economy Vol.14 No.1

This paper investigates the price returns and volatility linkages between the foreign exchange (KRW) and stock (KOSPI) markets in Korea, using the cointegration test, and bivariate GJR-GARCH model. Our findings from empirical analysis are summarized as follows. First, there is no long-term equilibrium relationship between the KRW and KOSPI markets. Second, exogenous variables (yen/dollar exchange rate and S&P 500 index) have strong impact on the returns of both the KRW and KOSPI. Third, with regard to return spillover, a uni-directional volatility spillover exists from the KOSPI market to the KRW market. Fourth, our empirical results provide no evidence of volatility spillover effect in the pre-crisis, but an evidence of uni-directional volatility spillover effect from the KRW market to the KOSPI market in the post-crisis period, implying that financial crisis improves linkages between these two markets. Finally, we do not find the asymmetric volatility spillover effect between two markets. Thus, investors in the Korean stock market and/or the foreign exchange market need to consider the relationship between these two markets as part of their investment decisions.

자동 혈액 분석 장비 ADVIA 120의 평가

강상훈,이은영,조경엽 대한임상병리사협회 2001 임상혈액검사학회 발표자료집 Vol.6 No.1