A17075-T6 시편의 절삭이송속도와 쇼트피닝 유무에 따른 피로수명 연구

김형태,신기훈,Kim, Hyoung-Tae,Shin, Ki-Hoon 한국생산제조학회 2007 한국생산제조학회지 Vol.16 No.4

This paper presents a study on the effects of feedrate and shotpeening on the fatigue life of A17075-T6 specimens. For this purpose, six groups of specimens, each of which consists of eight specimens, were first machined at six different feedrates(0.05, 0.10, 0.15, 0.20, 0.25, 0.30mm/rev). Half of eight specimens in each group were then peened and the others remained un-peened. Then, the fatigue life was measured by using 4-point rotatry bending machine. One observation was that the fast the feedrate was, the large the diameter of a specimen was. To make sure that the bending stress was the same in all cases, different loading conditions were thus applied to specimens based on their diameters. Next, comparison of fatigue life among twelve sets of specimens(six groups times two sets, peened and un-peened) was performed. Finally, based on machining cost analysis, a guideline for optimal feedrate was presented.

PIV Measurement of Velocity Profile in the 1/8 Scale CANDU6 Moderator Circulation Test

김형태,서한,차재은,방인철,Kim, Hyoung Tae,Seo, Han,Chan, Jae Eun,Bang, In Cheol The Korean Society of Visualization 2014 한국가시화정보학회지 Vol.12 No.1

The Korea Atomic Energy Research Institute (KAERI) has a scaled-down moderator test program to simulate the CANDU6 moderator circulation phenomena during steady state operation and accident conditions. In the present work a preliminary experiment using a 1/8 scaled-down moderator tank has been performed to identify the potential problems of the flow visualization and measurement in the scaled-down moderator test facility. With a transparent moderator tank model, a velocity field is measured with a Particle Image Velocimetry (PIV) technique under an isothermal state. The flow patterns from the inlet nozzles to the top region of the tank are investigated using PIV for a 1/8 scale moderator tank.

특이점분포방식(特異點分布方式)에 의한 비정상수중익문제(非正常水中翼問題)의 해석(解析) -제2보(第2報) 3차원(次元) 문제(問題)로의 확장(擴張)-

김형태,이창섭,Hyoung-Tae,Kim,Chang-Sup,Lee 대한조선학회 1983 大韓造船學會誌 Vol.20 No.3

In this paper a discrete-vortex-method(DVM) is presented for investigating the hydromechanics of the planar hydrofoils performing the undulatory motion which can be related to fish propulsion with carangiform mode. This is an extention of the authors previous work(1981) on the 2-dimensional hydrofoil. The applicability and accuracy of the present method are shown by means of comparing the calculated lifts and moments, and their distributions over the planforms with those in available references, for aspect ratio 1.0 and 2.0 rectangular hydrofoils and a swept-back hydrofoil of aspect ratio 2.0 from reduced frequency 0.1 to 0.5. The agreement is considered good. To assure the applicability of the DVM to the study of the propulsive performance of the oscillating planar hydrofoils, the convergence tests are performed. The mean thrust(in pure heave, this is wholly due to leading-edge suction), the mean power to maintain the motion and the hydromechanical efficiency are calculated for the rectangular hydrofoil of aspect ratio 8.0 and these are compared with the calculations by Chopra & Kambe(1977) and Lan(1979) for the same cases.

북한 에너지산업과 천연가스분야 투자에 따른 경제적 파급효과

김형태(Hyoung-Tae Kim),채정민(Jung-Min Chae),조영아(Young-Ah Cho),김진호(Jin-Ho Kim) 한국가스학회 2016 한국가스학회지 Vol.20 No.4

최근 북한은 경제난으로 인해 에너지 부문의 투자여력이 감소되었고 에너지 부문의 투자 감소는 다시 에너지 생산 감소라는 악순환이 반복되고 있다. 이런 상황을 살펴볼 때 북한의 경제상황이 나아지게 된다면 우선적으로 투자될 부문은 에너지부문이라 판단된다. 본 논문에서는 개성공단 내 천연가스 복합화력발전소 건설에 3,900억 원이 투자 되었다고 가정하고 북한경제와 남한경제에 미치는 경제적 파급효과를 계산하였다. 북한의 경제적 파급효과를 분석하기 위하여 2014년도 산업연관표(북한)를 작성하였고, 투입-산출모형을 이용하였다. 천연가스산업 투자의 파급효과는 10.12억 달러이다. 또한, 남한의 경제에 미치는 파급 효과를 분석하기 위해 2013년 산업연관표(남한)와 산업연관분석의 수요유도형 모형을 이용하였다. 천연가스산업 투자의 생산유발효과, 부가가치유발효과, 취업유발효과는 각각 2.02073, 0.62697, 8.99409으로 계산되었다. The economic crisis in North Korea has reduced its capacity to invest in the energy industries. The country is going through a vicious cycle of decreased investment in the energy industries and reduced energy production. This suggests that the energy industries would come to the top priority of investment once the economy improves. This paper calculated the economic ripple effect of the investment on North and South Korean economies based on the assumption that 390 billion won was invested in the construction of a natural gas combined-cycle power plant in Gaesong Industrial Complex. In order to analyze the economic ripple effect of the investment on North Korean economy, we constructed the inter-industry relation table of North Korea for year 2014 and used the input-output model. The ripple effect of the investment in the natural gas industry turned out to be 1.012 billion dollars. In order to analyze the effect of the investment on South Korean economy, we constructed the inter-industry relation table of South Korea for year 2013 and used the demand-driven model for inter-industry analysis. As a result, production, added-value and employment inducement coefficients of the investment in the natural gas industry were calculated as 2.02073, 0.62697 and 8.99409 respectively.

삼차신경통의 치료를 위한 삼차신경절 풍선압박술의 마취관리 -증례보고

김형태 ( Hyung Tae Kim ),안선경 ( Seon Kyeong An ),장인수 ( In Su Jang ),김형일 ( Hyoung Ihl Kim ) 대한마취과학회 2009 Korean Journal of Anesthesiology Vol.57 No.1

Trigeminal neuralgia is sudden, usually unilateral, severe brief stabbing recurrent pain in the distribution of one or more branches of the 5th cranial nerve. Treatments of trigeminal neuralgia include systemic trials of medications and surgical procedures such as microvascular decompression, stereotactic radiosurgery, percutaneous glycerol or alcohol rhizolysis, percutaneous radiofrequency rhizotomy, and percutaneous balloon compression (PBC). PBC of the trigeminal ganglion using a balloon catheter was introduced by Mullan and Lichtor in 1983. Since then, many papers have been published describing results of this technique. Typically, this procedure is performed under general anesthesia. However, little is known about the use of PBC for the treatment of trigeminal neuralgia in Korea. We report here our anesthetic management of percutaneous balloon compression of trigeminal ganglion for the treatment of the trigeminal neuralgia by total intravenous anesthesia. (Korean J Anesthesiol 2009; 57: 132~6)

CFX Simulation of a CS28-2 Experiment

Hyoung Tae Kim(김형태),Bo Wook Rhee(리보욱),Joo Hwan Park(박주환) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

A computational fluid dynamics (CFD) simulation tool for the CS28-2 high temperature experiment is developed with a CFX-10 software and the results obtained from the simulations are compared with the experimental data. The CS28-2 test is one of the experiments to understand the high-temperature fuel channel behavior and to establish the effectiveness of the moderator as a heat sink to demonstrate the safety of CANDU reactors. The main heat transfer characteristics of the CS28-2 are a super-heated steam convection and a radiation heat transfer from the hot rods to the surrounding cold wall. The CFX-10 predictions of the temperatures of the heater rods and the pressure tube are in good agreement with the measurement data for steady-state conditions.

2차원 초공동 유동의 중력과 자유표면 효과에 대한 수치해석

김형태(Hyoung-Tae Kim),이현배(Hyun-Bae Lee) 대한조선학회 2014 大韓造船學會 論文集 Vol.51 No.5

한⋅일 은행산업의 메타효율성 비교: 이윤을 바탕으로

김형태(Hyoung-Tae Kim),조일금(Il-Gum Cho),강상목(Sang-Mok Kang) 한일경상학회 2023 韓日經商論集 Vol.98 No.-

Purpose: This study aims to improve the competitiveness of the domestic banking industry by diagnosing the efficiency of the Japanese and Korean banking industries, which have similar financial environments such as long-term low growth and low interest rates. Research design, data, and methodology: The research method uses probabilistic frontier analysis (SFA) and the form of a profit function based on five years (2015- 2019) data for 35 banks in Korea and Japan. This study estimates the individual frontiers of Korean and Japanese banking groups, and estimates the meta-frontiers that encompass the individual frontiers of Korean and Japanese banks operating with different technologies. In addition, the international technology gap between two countries is measured and meta-profit efficiency is calculated using the profit efficiency of each country and the international technology gap. Through this verification process, the management characteristics of countries leading the meta-frontier and the banking industry in that country are confirmed. Furthermore, we regressively analyze the determinants of inefficiency for the profit and technology gap of the two national banking groups and draw implications. This study differs from previous studies in that it uses a probabilistic frontier analysis and a profit function for the international banking industry from a profit perspective. Results: As a result of empirical analysis, first, in terms of profit efficiency by country, the Bank of Korea group is more efficient. However, in the international technology gap, the Japanese banking group is considerably ahead of Korea. Accordingly, in terms of meta profit efficiency, the Japanese banking group is ahead of Korea, which is due to the international technology gap. Second, the meta profit efficiency of Japan’s three major urban banks is the highest with an average of 0.91 for five years, and among them, Mitsubishi UFJ Bank was found to be the leading bank among all the research target banks. Third, it was analyzed that the profit efficiency improvement effect occurs only when the market concentration (HHI index) of both countries’ banking groups is increased and the net loan ratio is lowered. Implications: Therefore, it was suggested that the banking industry of the two countries should increase their market dominance by increasing the beneficiary assets other than loans, because the increase in bad debts due to credit risk increases as the amount of loans increases and negatively affects the efficiency of banks.

4 채널의 Photo-plethysmogram 시스템 구현에 관한 연구(I)

김형태(Hyoung-Tae Kim),한순천(Soon-Chen Han),김정국(Jung-Kuk Kim),허웅(Woong Huh),박영배(Young-Bae Park) 대한전자공학회 2002 대한전자공학회 학술대회 Vol.2002 No.6

PCA 를 활용한 금융기관 재무건전성 규제

김형태(Hyoung Tae Kim),한상범(Sang Buhm Hahn) 한국증권학회 2000 Asia-Pacific Journal of Financial Studies Vol.27 No.1