• 한국기계연구소 소보
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• 통권20호
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• pp.79-87
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• 1990

Advanced ceramics have some excellent properties as the material for the mechanical component. It is, however, very difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. Thus it is required also by a strong boom of demands for development of Machinable ceramics with high machinability in the most of industries. In present research, experiments are carried out to compare the machinability of sample Machinable ceramics. A $\ell$N(Aluminum Nitride) with additives of BN(Boron Nitride), yttrium. CaO are turned with cut-off tool type tungsten carbide bite using conventional turning machine.

• EDISON SW 활용 경진대회 논문집
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• 제2회(2013년)
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• pp.425-430
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• 2013

본 연구에서 전산유체해석 프로그램인 EDISON_CFD를 이용하여 차세대 항공기 날개 형상으로 각광받고 있는 초음속 비행조건을 갖는 Busemann 형식의 복엽기 형상에 대한 공력특성을 연구하였다. 날개는 압축성 조건에서 2차원 에어포일로 간략화 하여 모델링하였으며, 마하수에 따라 발생하는 충격파와 팽창파의 상호작용을 통한 소닉붐의 감소 형태를 분석해 보고, 마하수에 따른 항력계수를 얻어내었으며, 익형과 항력계수, 소닉붐의 상관관계를 분석하여 초음속항공기에서 복엽기 형상이 가지는 장단점에 대하여 연구하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.865-867
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• 1996

This paper presents the power system basic planning in urban area, when the superconductive power cable is installed in power system in the future. To decide the proper superconductive cable routes, load flow calculation was carried out based on the long term load forecasting of kyoungin area. The simulated results show that installation of superconductive power cable is able to overcome rapidly growing power demand of unban area.

• 기술사
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• 제30권2호
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• pp.20-35
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• 1997

At present Internet, a huge network connecting many computers in the world, has become a major boom to business. It seems to change not only telecommunications, but also changes the business world. It was utilized by a maximum of about 1,000,000 at the end of the 1980's. This figure has increased dramatically to approximately 40,000,000 at present. This enormous increase has been from two reasons. One is that an open door for businesses begun in 1990. This fact called to account a new interest of many enterprises looking to expand their business through Internet. Prior to that Internet was confined to academic utilization and not used for business purposes. The other reson is that a method was developed where desired information could be easily searched. This article describes the fundamentals of Internet so that one should know the history of Internet and the connection method to use it in practice in Korea. The splendor of Internet cannot be understood until it is tested In practice. The readers are strongly urged to participate in the Internet.

• Journal of Astronomy and Space Sciences
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• 제4권1호
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• pp.55-63
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• 1987

세계 제 2 차대전이 끝난 이후로부터 40여년간, 현대 관측천문학을 이끌어 온 Palomar 산의 500cm 반사망원경은 드디어 차세대망원경에게 leadership을 넘겨주게 되었다. 자금염출이 여의치 않아 그동안 부진했던 초대형망원경 건설이 드디어 boom을 일으키게 된 것이다. 가주공과대학의 10m 반사망원경이 제작 중에 있고, Ohio주립대학도 10m 쌍통반사망원경 건립을 추진 중에 있고, 일본도 7.5m 반사망원경 건립을 검토 중이다. 한국은 1.5m~2m 반사망원경 제작이 구체화되어가고 있으니, 1970년, 불과 40cm 반사경 1대만 갖고 고군분투하던 그때를 초기하면 실로 감계무량하다 아니할 수가 없다. 그러나 NASA는 또 한편, 차세대망원경으로서 Space Shuttle을 이용하여 위성망원경을 발사할 계획을 1965년에서부터 구상하여 수차에 걸친 발의·부결을 거듭한 끝에, 드디어 1977년, 미국회의 건조인준을 얻었다.

• 한국인구학
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• 제14권2호
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• pp.78-87
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• 1991

본 연구는 대도시의 인구이동률의 장기적 추세를 분석하기 위하여 시도되었다. 본 연구에서는 멕시코의 중소도시인 오하카(Oaxaca)에서 구역별로 추출된 633가구를 대상으로, 그들의 거주지 이동상황 및 이에 영향을 미치는 인구.사회학적 요인에 관한 설문을 실시하였다. 연구결과, 가족의 거주지 이동률은 결혼후 5년 이내가 년간 23.23 퍼센트로서 가장 높았는데, 이것은 결혼초기에 출산과 관련한 주거공간 요구의 급격한 증가가 주된 원인인 것으로 해석되었다. 또한 연대별로는 1960년대에 특히 많은 주거지 이동이 있었는데, 이는 이 시기의 범 세계적인 아기풍년(Baby Boom)에 따른 급격한 자녀수의 증가와 관련된 거주공간의 수요확대로 인한 현상으로 해석되었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.115-120
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• 2004

This paper concerns the active aeroelastic control of flapped wing systems exposed to blast and/or the sonic boom in an incompressible flow field. This is achieved via implementation of a robust estimation capability (sliding mode observer: SMO), and of the use of the deflected flap as to suppress the flutter instability or enhance the subcritical aeroelastic response to blast loads. To this end, a control methodology using LQG(Linear Quadratic Gaussian) in conjunction with SMO is implemented, and its performance toward suppressing flutter and reducing the vibrational level in the subcritical flight speed range is demonstrated. Moreover, its performances are compared to the ones provided via implementation of conventional LQG with Kalman filter.

• 드라이브 ㆍ 컨트롤
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• 제13권1호
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• pp.49-53
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• 2016

The accurate calculation of bucket tip position has a large influence on showing the motion of an excavator on the display device of the excavator and controlling the excavator automatically. It is generally known that Inertial Measurement Unit (IMU) sensors are more accurate than accelerometer-based sensors while the boom, arm or bucket moves because additional forces beyond gravity add additional acceleration to the sensors. To prove the accuracy difference between the two types of sensors, a position recognition system using an accelerometer-based sensor and an IMU sensor is implemented on the excavator. The experimental results show that the system using the IMU sensor significantly reduces the position recognition error while bucket moves and additional force beyond gravity exists.

• 한국산림과학회지
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• 제95권5호
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• pp.601-604
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• 2006

This study compared the accuracy of partial multivariate and vector autoregressive models for lumber demand prediction in Korea. The partial multivariate model has three explanatory variables; own price, construction permit area and dummy. The dummy variable reflected the boom of lumber demand in 1988, and the abrupt decrease in 1998. The VAR model consists of two endogenous variables, lumber demand and construction permit area with one lag. On the other hand, the prediction accuracy was estimated by Root Mean Squared Error. The results showed that the estimation by partial multivariate and vector autoregressive model showed similar explanatory power, and the prediction accuracy was similar in the case of using partial multivariate and vector autoregressive model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.66.1-66
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• 2001

As choosing proper length of boom of container crane according as sort of vessels(18, 22, 24 columns and so on), reinforcing of capacity of DC motor to transport heavy loads, it´s structure being oversized with flexibility and durability, the study is progressing on the automation for convenient operation and effective control. We often cannot but work slowly caused by swaying(pitching, rolling) of vessel. We can get productivity and efficiency by getting over it. The factors of swaying, as fellow; - wave caused by vessels around moving - wind and wave caused by weather change - vessel´s moving by change of load weight - tide - move of vessel According to ...