• 해양환경안전학회지
• /
• 제5권2호
• /
• pp.45-55
• /
• 1999

The majority of fishing vessels(under 20 tonnages) in Korea have a high casualty accident of the flood and capsizing occurred by lack of stability. Actually, it is so difficult to make out the data of inclining and stability tests of small fishing vessels after building, because most of them were built on experiences of manufacturer. According to above reasons, the aim of this study is an attempt to propose a stability criteria of small fishing vessels as follows: Firstly, it is examined that the stability is driven from a transverse metacenter height of actual ships, which is able to obtain a basic drawing and stability data. Secondly, it is examined the heeling at high-speed turning, and the period of rolling according to B/D(breadth/depth). Finally, it is suggested the stability criteria by using a dynamic state which is applied in passenger boat and fishing vessels over 24 meters.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.150.5-150
• /
• 2001

This paper deals with a modified repetitive control method for compensating automatic gauge control (AGC) to reduce the effect of skid mark which directly influence the quality of products in plate mill process. Since the skid mark on the plate have thermal difference, it makes a different stretching rate and deflection of thickness. Firstly, the (AGC) system and the plate mill process are described by considering function in each control levels. The skid mark of the plate in practical control fields is shown. Also, its frequency variation is given by on-line FFT analysis method. Secondly, a key idea of the modified repetitive control method with time varying period disturbance is represented and compared with standard repetitive control method. Lastly, in simulation ...

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.1412-1416
• /
• 2003

Induction Heaters are commonly used in heating steel strip product, because it can rapidly and efficiently heat steel strip/bar. In this study, a inductive heating model is developed and the predictions are compared with measured temperatures. The temperatures are measured from POSCO thin-slab rolling facility (so called Minimill). Induction heater is installed between reduction unit and holding furnace This induction heater raise the temperature of steel bars from $930^{\circ}C$ to about $1100^{\circ}C$ which gives the required temperature for finishing mill process after holding period at holding furnace. Unlike other simple equation models, this model allows us to predict temperature profiles of sections of steel bars.

• 한국항해항만학회지
• /
• 제28권5호
• /
• pp.353-358
• /
• 2004

ISSC 스팩트럼을 기초로 종래의 불규칙파가 아닌 새로울 과도 불규칙파를 설계하였다. 이 설계불규칙파를 장수조에서 조파기를 사용하여 발생시키고, 파고계와 6자유도계를 설치하여서 모형선의 횡동요 운동을 계측하였다. 모형선의 최대 횡동요각의 실험값과 이론값을 비교하여 단기 해상에서 발생 가능한 횡동요 피크치를 추정하는 방법에 관하여 검토하였다.

• 한국항해학회지
• /
• 제22권2호
• /
• pp.89-98
• /
• 1998

In the field of research of seakeeping quality, much development has been made incent years using the method of calculation based on the strip theory. It is indispensable to grasp quantitatively the seaworthiness of a ship in order to draw correct design at initial stage and to perform proper operations at sea services. In this paper, the responses of three fishing vessels are calculated using statistical and spectral analyzing method to get the characteristics of the motion response. From the theoretical result we know that the significant values of the pitching and rolling motion can be signiicantly affected by not only the ship's tonnage but also the mean wave period in spite of the similar sea environment. So we can apply these expected results to the safe maneuvering and fishing operations in rough weather conditions by combining environmental circumstance with the stability condition of vessels.

• 대한기계학회논문집B
• /
• 제32권10호
• /
• pp.810-815
• /
• 2008

To enhance aerodynamic efficiency of the Smart Un-manned Aerial Vehicle(SUAV) during the transition period, wingtip fence is attached at the end of wing. The application of wingtip fence is to reduce the effect of the separated flow caused by the nacelle on the wing especially when the tilting angle of nacelle is more than 30 degrees. To compare the effect of with and without wingtip fence, flow visualization and measurement of the aerodynamic coefficients using the pyramidal type external balance are done. Result of forces and moments measurement shows that the slope of lift coefficient is increased 18% and rolling moment of SUAV especially 60 & 90-degree tilting is changed in favorable manners with wingtip fence.

• 산업경영시스템학회지
• /
• 제11권17호
• /
• pp.47-54
• /
• 1988

Korean National Railroad(K.N.R) playing a important role in land transportation gives us many problems to solve considering proper management of National Budget and development of the state of operation by maintaining train parts rationally as public services. According this study is to show inventory provision system for deciding the safety inventory level as the better rational method. Bibliography for this study is limited to only three kinds of seven brakes-shoe which is produced by T workshop in Korean National Railroad. To reduce the holding cost coming from the want of the stock and shortage cost of the stock expected. This study is to present a ratio of shortage on the stock permitted for the last definite period and the demand result forecast per month.

• The Journal of Asian Finance, Economics and Business
• /
• 제9권3호
• /
• pp.181-193
• /
• 2022

This paper seeks to investigate major macroeconomic factors and bond yield interactions in Thai bond markets, with the goal of forecasting future bond yields. This study examines the best predictive yields for future bond yields at different maturities of 1-, 3-, 5-, 7-, and 10-years using time series data of economic indicators covering the period from 1998 to 2020. The empirical findings support the hypothesis that macroeconomic factors influence bond yield fluctuations. In terms of forecasting future bond yields, static predictions reveal that in most cases, the BVAR model offers the best predictivity of bond rates at various maturities. Furthermore, the BVAR model has the best performance in dynamic rolling-window, forecasting bond yields with various maturities for 2-, 4-, and 8-quarters. The findings of this study imply that the BVAR model forecasts future yields more accurately and consistently than other competitive models. Our research could help policymakers and investors predict bond yield changes, which could be important in macroeconomic policy development.

• 한국경제지리학회지
• /
• 제25권1호
• /
• pp.147-170
• /
• 2022

이 논문은 70개 수도권 시군구 아파트 매매가격의 주간 수익률을 대상으로 그 변동 순환과 현 정부의 집권 시기 등을 고려하여 전체기간(2008년 4월~2021년 8월), 가격 급등기 이전(2008월 4월~2018년 10월), 그리고 가격 급등기(2018년 11월~2021년 8월)로 나누어 확산효과를 분석한다. 이러한 분석으로부터 얻어진 분석 결과를 요약하면 다음과 같다. 첫째, 확산효과에 대한 분석은 시기에 따라 기존의 연구 결과와 유사하기도 하지만 다르기도 하다. 전체기간과 가격 급등기 이전 시기에 대한 확산효과 분석은 수도권 아파트시장에서 '강남' 효과가 실재한다는 것을 보여준다. 반면에 가격 급등기에 대한 확산효과 분석은 이전과는 상이한 결과를 나타낸다. 순환 표본의 분석을 통해 계산된 확산효과 지수는 수도권 아파트 매매가격 순환의 하강기에는 확산효과 지수가 낮아지고, 반면에 상승기에는 그 반대의 추세를 보여준다. 확산효과 지수의 정점과 정책 개입 간의 타이밍을 보면 대체로 2017년에는 확산효과 지수의 정점 이후, 2018년과 2019년에는 정점 이전, 2020년 이후 정점 무렵이나 정점 이후에서 정부의 정책 개입이 이루어진 것으로 나타난다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.540-545
• /
• 2010

2009년 3월 19일 도시철도차량의 내구연한 관련 법령이 개정되면서 도시철도차량이 최장 40년까지 사용 가능하게 되었다. 이는 차량제작 기술의 발전과 더불어 소재와 부품의 품질 향상으로 내구성이 우수해졌고 체계적인 관리와 노후 부품의 교체 등으로 도시철도 차량의 수명이 길어졌기 때문이라고 판단된다. 도시철도 차량의 안전은 승객의 안전과 직접적인 관계가 있으므로 안전성을 최우선적으로 고려하여야 하며 내구연한 연장을 위해서는 더욱 정밀한 안전 검정이 필요하다. 이에 내구연한이 도래한 전동차는 개정된 "도시철도차량의 정밀진단지침"에 따라 정밀진단을 실시하여야 한다. 본 연구는 내구연한 연장 관련 법령 개정 이후 최초로 정밀진단을 시행하고 있는 부산교통공사의 사례를 통해 정밀진단 시행기관과 도시철도 운영기관에 정밀진단에 대한 진단기법의 방향을 제시하고자 한다.