CP강의 디스크레이저 용접부의 경도특성에 미치는 B 함유량의 영향

박태준,유정우,강준일,한태교,진광근,강정윤,Park, Tae-Jun,Yu, Jung-Woo,Kang, Jun-Il,Han, Tae-Kyo,Chin, Kwang-Keun,Kang, Chung-Yun 대한용접접합학회 2011 대한용접·접합학회지 Vol.29 No.1

CP steel was developed to reduce the weight and increase the strength of car body. When it was welded using state-of-the-art disk laser welding, the effected of boron on the microstructure and hardness were investigated. Welding power was fixed at 3.5kW and welding speeds were 4,8 and 12m/min. Full penetration occurred in welding speed of 12m/min and weld bead was almost unchanged with boron contents. But the welding speed increased, the upper and lower bead were narrowed. In a welding speed of more than 8m/min, underfill defects were formed on the bead bottom. The hardness of weld zone was somewhat fluctuation in fusion zone and HAZ showed the highest hardness values. The hardness of each region showed little change with the boron contents, and softening phenomenon occurred in the HAZ near the base metal regardless of the boron contents.

Al-Si 용융도금된 11%Cr 페라이트 스테인리스강, STS409L GTA 용접부의 미세조직과 경도

박태준,공종판,나혜성,강정윤,엄상호,김정길,우인수,이종섭,Park, Tae-Jun,Kong, Jong-Pan,Na, Hye-Sung,Kang, Chung-Yun,Uhm, Sang-Ho,Kim, Jeong-Kil,Woo, In-Su,Lee, Jong-Sub 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.3

Ferritic stainless steels, which have relatively small thermal expansion coefficient and excellent corrosion resistance, are increasingly being used in vehicle manufacturing, in order to increase the lifetime of exhaust manifold parts. But, there are limits on use because of the problem related to cosmetic resistance, corrosions of condensation and high temperature salt etc. So, Aluminum-coated stainless steel instead of ferritic stainless steel are utilized in these parts due to the improved properties. In this investigation, Al-8wt% Si alloy coated 409L ferritic stainless steel was used as the base metal during Gas Tungsten Arc(GTA) welding. The effects of coated layer on the microstructure and hardness were investigated. Full penetration was obtained, when the welding current was higher than 90A and the welding speed was lower than 0.52m/min. Grain size was the largest in fusion zone and decreased from near HAZ to base metal. As welding speed increased, grain size of fusion zone decreased, and there was no big change in HAZ. Hardness had a peak value in the fusion zone and decreased from the bond line to the base metal. The highest hardness in the fusion zone resulted from the fine re-precipitation of the coarse TiN and Ti(C, N) existed in the base metal during melting and solidification process and the presence of fine $Al_2O_3$ and $SiO_2$ formed by the migration of the elements, Al and Si, from the melted coating layer into the fusion zone.

스마트 스피커 대상 가청 주파수 대역을 활용한 적대적 명령어 공격 방법 제안

박태준,문종섭,Park, Tae-jun,Moon, Jongsub 한국인터넷정보학회 2022 인터넷정보학회논문지 Vol.23 No.4

최근 스마트 스피커의 기능이 다양해지면서 스마트 스피커의 보급률이 증가하고 있다. 보급이 증가함에 따라 스마트 스피커에 대해 비정상적인 행위를 발생시키는 기법이 제안되고 있으며 여러 가지 공격 중 Voice Controllable System(VCS)에 대해 비정상적인 행위를 발생시키는 DolphinAttack은 초음파(f>20kHz)를 이용하여 사용자의 인식 없이 VCS를 제3자가 제어하는 방법이다. 하지만 기존의 제어 방법은 초음파 대역을 사용하기 때문에 초음파 신호를 출력할 수 있는 초음파 스피커나 초음파 전용 장비의 설치가 필요했다. 본 논문에서는 추가적인 장비, 즉, 초음파 장비의 설치 없이 사람의 가청 주파수 대역이지만 노화에 의해 듣기 힘든 주파수(18k~20kHz)로 변조된 음성신호를 출력하여, 스마트 스피커를 제어하는 방법을 제안한다. 스마트 스피커의 경우 마이크가 내장되어 있어, 변조된 음성신호를 수신할 수 있다. 본 논문에서 제안한 방법으로 수행한 결과, 가청 대역임에도 불구하고 사람은 음성명령을 인식하지 못하였으며, 스마트 스피커에 대해 82~96%의 확률로 제어가 가능했다. Recently, the functions of smart speakers have diversified, and the penetration rate of smart speakers is increasing. As it becomes more widespread, various techniques have been proposed to cause anomalous behavior against smart speakers. Dolphin Attack, which causes anomalous behavior against the Voice Controllable System (VCS) during various attacks, is a representative method. With this method, a third party controls VCS using ultrasonic band (f>20kHz) without the user's recognition. However, since the method uses the ultrasonic band, it is necessary to install an ultrasonic speaker or an ultrasonic dedicated device which is capable of outputting an ultrasonic signal. In this paper, a smart speaker is controlled by generating an audio signal modulated at a frequency (18 to 20) which is difficult for a person to hear although it is in the human audible frequency band without installing an additional device, that is, an ultrasonic device. As a result with the method proposed in this paper, while humans could not recognize voice commands even in the audible band, it was possible to control the smart speaker with a probability of 82 to 96%.

간 이식 예정 환자의 구강건강상태 및 치과치료 요구도에 관한 연구

박태준,고홍섭,Park, Tae-Jun,Kho, Hong-Seop 대한안면통증구강내과학회 2009 Journal of Oral Medicine and Pain Vol.34 No.1

Liver transplantation is definitive treatment for the patients suffering from hepatitis, severe liver cirrhosis and liver cancer. In these patients, systemic infections under immunosuppression may occur easily. Therefore, primary object of dental treatments before liver transplantation is absolute removal of oral infection source. In addition, comprehensive dental management plan is essential for success of liver transplantation. The present study has been performed to investigate decayed, missing and filled permanent teeth index(DMFT index), degree of oral hygiene, past medical history, need of dental treatment, completion of dental treatment need and time interval between dental visit and operation date of liver transplantation in liver transplant candidates. Obtained results were as follows; 1. Decayed teeth of the patients were 2.68, missing teeth were 4.02 and filled teeth were 3.42. DMFT index was 10.12. 2. Twenty percents of patients showed moderate to severe food impactions, 42.2% of patients had moderate to heavy calculus and 37.8% of patients displayed gingival inflammation with swelling. 3. Patients needed periodontal treatments more than any other dental treatments. Periodontal treatments were needed for 88.9% of patients, operative & endodontic treatments were 46.7% of patients and 33.3% of patients needed for oral & maxillofacial surgical treatments. 4. Among 90 patients, time interval between scheduled operation date of liver transplantation and dental visit was within 2 weeks for 32.2% of patients, within 1 week for 20.0% of patients. In conclusion, most liver transplant candidates needed dental treatments for removal of potential infection sources. However because of insufficient interval between dental visit and operation date, they had taken liver transplantation procedures without comprehensive dental management. Development of preventive and comprehensive dental management program is mandatory for these patients. Cooperative interdisciplinary management will play a positive role for successful liver transplantation.

N타입 결정질 실리콘 웨이퍼 두께 및 알루미늄 페이스트 도포량 변화에 따른 Bowing 및 Al doped p⁺ layer 형성 분석

박태준,변종민,김영도,Park, Tae Jun,Byun, Jong Min,Kim, Young Do 한국재료학회 2015 한국재료학회지 Vol.25 No.1

In this study, in order to improve the efficiency of n-type monocrystalline solar cells with an Alu-cell structure, we investigate the effect of the amount of Al paste in thin n-type monocrystalline wafers with thicknesses of $120{\mu}m$, $130{\mu}m$, $140{\mu}m$. Formation of the Al doped $p^+$ layer and wafer bowing occurred from the formation process of the Al back electrode was analyzed. Changing the amount of Al paste increased the thickness of the Al doped $p^+$ layer, and sheet resistivity decreased; however, wafer bowing increased due to the thermal expansion coefficient between the Al paste and the c-Si wafer. With the application of $5.34mg/cm^2$ of Al paste, wafer bowing in a thickness of $140{\mu}m$ reached a maximum of 2.9 mm and wafer bowing in a thickness of $120{\mu}m$ reached a maximum of 4 mm. The study's results suggest that when considering uniformity and thickness of an Al doped $p^+$ layer, sheet resistivity, and wafer bowing, the appropriate amount of Al paste for formation of the Al back electrode is $4.72mg/cm^2$ in a wafer with a thickness of $120{\mu}m$.

Field Voice

박태준,Park, Tae-Jun 대한전기협회 2011 전기저널 Vol.416 No.-

직무요구가 직무매너리즘과 조직몰입에 미치는 영향

김이태(Kim, Yi-Tae)박수진(Park, Su-Jin)박태준(Park, Tae-Jun) 대한관광경영학회 2015 觀光硏究 Vol.30 No.5

본 연구는 직무요구와 직무매너리즘 그리고 조직몰입 간의 관계를 규명하기 위한 실증분석 연구이다. 이를 위해 먼저 직무요구에 따른 직무매너리즘에 대해 살펴보고, 직무매너리즘이 조직몰입에 미치는 영향을 분석한 후 이들 간의 관계에 인지된 조직지원의 조절효과가 존재하는지를 규명하였다. 실증분석은 부산시 소재 전시 · 컨벤션산업 종사자 220명을 대상으로 실시하였고 연구가설 검증은 다중회귀분석 및 위계적 회귀분석을 실시하였다. 연구결과 다음과 같다. 첫째, 직무요구 중 역할모호성, 역할갈등 및 역할과부하 중 역할갈등은 직무매너리즘 중 3가지 하위요소(안정감추구, 수동적태도, 무의식적태도)에 영향을 미쳤으며, 역할모호성과 역할과부하는 부분적으로 영향을 미치는 것으로 나타났다. 둘째, 직무매너리즘이 조직몰입에 부정적인 영향을 미치는 것으로 나타났으며, 마지막으로 직무매너리즘과 조직몰입과의 관계에 인지된 조직지원의 조절효과가 부분적으로 있음을 확인 하였다. 따라서 본 연구에서의 시사점은 전시 · 컨벤션산업 종사자들이 경험하는 직무요구가 부분적으로 직무매너리즘에 대해 동기유발 하는 것으로 알 수 있다. 종사자들의 직무매너리즘 지각은 조직몰입에 부정적인 영향을 미치는 것으로 나타났다. 또한 직무매너리즘을 느낀다 하더라도 조직차원에서 종사자들에게 관심을 가지고 공헌에 대해 가치를 인정한다면 조직몰입에 대한 부정적인 영향을 완화시켜 조직몰입을 유도할 수 있음을 알 수 있었다. This purpose of this research were to (1) investigate factors of Job Demands and find out which factors have more impacts on the Job Mannerism, (2) identify the relationship between Job Mannerism and organizational commitment, and Finally, investigate a moderating role of a perceived organizational support(POS) between job mannerism and organizational commitment. The structural model was tested using the empirical data collected from 220 employees. The results indicated that (1) Job Demands were partly significant effect on the Job Mannerism, and (2) Job Mannerism had Negative impact on the Organizational Commitment, and (2) there were partly significant moderate effect on the relationship between Job Mannerism and Organizational Commitment. Based on the data analysis results theoretical/managerial implications were discussed.

FHS VaR를 이용한 이자율 스왑 증거금제도

박태준 ( Tae Jun Park ) 한국금융공학회 2015 금융공학산학연구 Vol.1 No.-

본 연구는 장외파생상품의 CCP(Central Counterparty: 중앙청산소) 청산에 청산증거금 산출방식에 대한 연구이며 특히 IRS(Interest Rate Swap: 이자율 스왑)의 증거금제도에 대해 분석하였다. 금융위기 이후 CCP에 대한 중요성이 커져 2009년 9월 피츠버그에서 개최된 G20정상회담에서 표준화된 장외파생상품의 CCP 청산의무화를 합의하였다. 우리나라의 경우 2014년 6월부터 IRS에 대한 CCP 청산이 의무화되었고, 그 다음 장외파생상품으로는 NDF (Non-Deliverable Forward: 차액결제선물환)에 대한 CCP 청산서비스가 시작될 전망이다. 청산 대상인 장외파생상품의 특성에 맞고 해당상품의 실제 리스크를 반영하는 증거금을 산출하는 것은 중앙청산소에 있어 매우 중요한 일이다. 해외 주요 청산소는 증거금을 산출할 때 FHS(Filtered Historical Simulation) VaR(Value at Risk) 방식을 사용하고 있다. FHS VaR에 대한 분석을 통해 KRX의 증거금제도 개선의 근간을 형성하고자 한다. We Analyse initial margin systems of CCP for OTC products, especially IRS (Interest Rate Swap). After the 2007-2008 global financial crisis, OTC market needed more transparency about exposure of counterparties. At the Pittsburg Summit in September 2009, G-20 leaders agreed that all standardized OTC derivative contracts should be cleared through CCP by the end of 2012. In Korea, IRS should be cleared in KRX-CCP from June 2014. Next to IRS, KRX-CCP has the plan for NDF(Non-Deliverable Forward) clearing. It is very important to design initial margin system which is adapted to the OTC products and appropriate to their real exposures. Most of major CCPs adopt FHS(Fi1tered Historical Simulation) VaR in calculating initial margin. I analyse FHS VaR margin system for reforming the KRX-CCP margin system.

토크 컨버터 내압 피로 해석

박태준(Tae-Jun Park),장영기(Young-Gi Jang),장재덕(Jae-Duk Jang),주인식(In-Sik Joo) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2007 No.11

기업 자본적지출 공시 주위에서의 기관투자자 거래행태

박태준 ( Tae-jun Park ),박진모 ( Jin-mo Park ) 한국생산성학회 2020 生産性論集 Vol.34 No.1

This study examines the institutional investor’s trading behavior around corporate’s capital expenditure announcements in terms of free cash flow hypothesis and the investment opportunities hypothesis. Jensen(1986) argues that managers will invest free cash flow in wasteful investments rather than pay it out to shareholders. The potential agency costs of capital expenditure are arguably higher for high-free cash flow firms. On the other hand, capital expenditure by low-free cash flow firms increase the chance the firm will seek new external financing. Free cash flow agency costs may depend on the firm's investment opportunities. Prior research shows that market reaction to a capital expenditure announcement is related to a firm’s investment opportunities, Tobin's q. Tobin's q is the ratio of the market value of the firm's assets to their replacement cost. There are evidences somewhat weak, supportive of the free cash flow hypothesis in explaining capital expenditure announcement-period returns. So, we investigate whether investment opportunities and free cash flow play an important role in explanation of the market response to such announcements. In other words, we tests the market response on capital expenditure announcements through investment opportunities hypothesis and free cash flow hypothesis. Most of the existing research on this area has used U.S data, but little is known about Korean evidence. Using KOSPI data over the period of 2000-2013, this paper mostly analyses the samples separated by Tobin's q and free cash flow. The main results are as follows; First, institutional investors tend to buy shares in the disclosure of capital expenditures by companies with many future investment opportunities and vice versa. But this relation is not significant in the OLS analysis. Second, low-free cash flow and high-q firms have a significant positive abnormal trading volume around the disclosure of capital expenditures, meanwhile high-free cash flow and low-q firms have an significant negative abnormal trading volume. But analysis for personnel investor’s trading volume shows insignificant relation with free cash flow or future investment opportunities. These results mean that institutional investors sell shares for companies with relatively small free cash flows and many future investment opportunities, while buy shares for those with relatively large free cash flows and little future investment opportunities.