• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.256-261
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• 2008

최근 사회 경제적 요구의 증가, 건설기술 및 공법의 발전, 고객의 다양화 등 건설 환경의 급격한 변화로 인해 고층건물이 과거에 비해 크게 증가하고 있으며, 고층화 및 고급화 경향에 따라 고층 오피스공사의 외부마감으로만 사용되던 커튼월공사가 고층 아파트 및 주상복합의 외부마감으로 확대 사용되고 있다. 전체 공사비의 $10{\sim}15%$를 차지하는 주요공정인 커튼월 공사는 최근 공기단축을 목적으로 골조공사가 시작한 일정시점 이후부터 커튼월 공사를 동시에 시작하는 방식인 적층공법이 많이 사용되고 있다. 하지만 커튼월 적층공법은 두 작업이 동시에 진행됨으로써 발생되는 작업간 간섭에 의해 커튼월 공사의 공기가 지연이 되는 문제점이 있는데, 노무자 투입에 관한 방법론과 전산화 시스템의 부재로 인해 효율적인 해결책이 제시되지 못하고 있는 실정이다. 이를 위한 방안으로 가상공간에서 실제공사를 수행하기 전 미리 문제점을 예측하고 분석할 수 있는 건설 시뮬레이션 기법이 있지만 아직 건축공사에는 그 적용이 전무한 실정으로 이 논문에서는 대표적인 건설 시뮬레이션 기법인 사이클론을 이용하여 커튼월 적층공법의 작업 프로세스 일반화 모델을 개발하여 노무 및 장비 자원의 투입량에 따른 작업 생산성을 예측하였다. 이 연구의 결과는 현장관리자의 노무 및 장비 투입을 위한 효과적인 의사결정 도구로 활용될 수 있으며, 공기지연 시 원인분석 도구로 활용될 수 있을 것으로 기대된다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권1호
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• pp.35-40
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• 2005

In this paper, we designed and fabricated the variable impedance line by using the DGS(Defected Ground Structure) which is useful in mounting the external lumped elements. Also we used a varactor diode as Control device stuff at the proposed variable impedance line. We are able to change the impedance of transmission line as varied the capacitance of varactor diode by adjusting DC bias. The impedance variation of the proposed DGS line is about maximum 70 Ω. We will study about the application of DAM(Direct antenna modulation) in the future work.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.282-285
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• 2000

Four helical resonators are distributed in a 2 ${\times}$ 2 array by modifying upper part of the conventional reactive ion etching(RIE) type LCD etcher in order to prepare a large area plasma source. Since the resonance condition of the RF signal to the helical antenna, one RF power supply is used for delivering the power efficiently to all four helical resonators without an impedance matching network Previous work of 2 ${\times}$ 2array inductively coupled plasma(ICP)requires one matching circuit to each ICP antenna for more efficient power deliverly Distributions of ion density and electron temperature are measured in terms of chamber pressure, gas flow rate and RF power . By adjusting the power distribution among the four helical resonator units, argon plasma density of higher than 10$\^$17/㎥ with the uniformity of better than 7％ can be obtained in the 620 ${\times}$ 620$\textrm{mm}^2$ chamber.

• Steel and Composite Structures
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• 제21권5호
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• pp.1121-1144
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• 2016

This paper presents a displacement-based finite element procedure for second-order distributed plasticity analysis of planar steel frames with semi-rigid beam-to-column connections under static loadings. A partially strain-hardening elastic-plastic beam-column element, which directly takes into account geometric nonlinearity, gradual yielding of material, and flexibility of semi-rigid connections, is proposed. The second-order effects and distributed plasticity are considered by dividing the member into several sub-elements and meshing the cross-section into several fibers. A new nonlinear solution procedure based on the combination of the Newton-Raphson equilibrium iterative algorithm and the constant work method for adjusting the incremental load factor is proposed for solving nonlinear equilibrium equations. The nonlinear inelastic behavior predicted by the proposed program compares well with previous studies. Coupling effects of three primary sources of nonlinearity, geometric imperfections, and residual stress are investigated and discussed in this paper.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.459-464
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• 2001

A mathematical model has been developed to describe the turbulent and reversed flow with convective heat transfer in a cylindrical combustion chamber. By using the mathematical model for high temperature flow enables the trends in overall heat transfer rates to be predicted. The model was applied to the design of the combustion chamber. The influences of the size of air inlet and inlet velocity were investigated for process optimization. Through modelling work it is found that the heat transfer rate to the chamber wall may be enhanced by adjusting the air flow and heat transfer pattern through selecting the air inlet condition. Internal plate has less influence to the heat transfer characteristics.

• 한국생산제조학회지
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• 제6권4호
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• pp.54-64
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• 1997

This paper provides a practical control scheme called three-step input method in order to minimize both robot response time and the resulting residual vibration when the robot manipulator reaches its defined end point. This work is concerned with defining a simple practical method to utilize step inputs to achieve optimum response. The optimum response is achieved by using a self- adjusting input command function that is obtained during a real time processing . The practicality of this control scheme is demonstrated by using an analog computer to simulate a simulate a simple flexible robot and conventional servo controller. The experiments focus on point-to-point movement. Also, this method requires little computational effort through the intelligent use of conventional servo control technology and the robot's vibration characteristics.

• 한국전기전자재료학회논문지
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• 제31권2호
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• pp.107-111
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• 2018

In this study, we designed the temperature coefficient of resistance (TCR) and heat radiation properties of shunt fixed resistors by adjusting the atomic composition of a metal alloy resistor, and fabricated a resistor that satisfied the designed properties. Resistors with similar atomic composition of copper and nickel showed low TCR and excellent shunt fixed resistor properties such as short-time overload, rated load, humidity load, and high temperature load. Finally, we expect that improved sensor accuracy will be obtained in current-distribution-type shunt fixed resistor for IoT sensors by designing the atomic composition of the metal alloy resistor proposed in this work.

• 한국진공학회지
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• 제4권S1호
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• pp.145-150
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• 1995

PZT thin films were fabricated on Pt/Ti/SiO2/Si substrates at $500^{\circ}C$ by ECR-PECVD for the application to the charge storage capacitor of ULSI DRAMs. Perovskite single phase PZT films were obtained by controling the film compositional ratio Pb/(Zr+Ti) close to 1. The anion concentrations in the PZT films were successfully controlled by adjusting the flow rates of each MO sources. Capacitance of a typical 94 nm thick PZT film prepared at $500^{\circ}C$ in this work was about 5.3 uF/$\textrm{cm}^2$, which corresponds to the equivalent SiO2 thickness of 0.65nm.

• Industrial Engineering and Management Systems
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• 제6권2호
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• pp.146-157
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• 2007

This paper discusses two algorithms for recommending notebook computer (NBC) and workstation adjustments so that the user can assume an ergonomic seated posture during NBC operation. Required input data are the user's anthropometric data and physical dimensions of the NBC and the workstation. The first algorithm is based on an assumption that there are no workstation constraints while the second algorithm considers the actual seat height and work surface height. The results from the algorithms include recommendations for adjusting the NBC (tilt angle of the NBC base unit, angle between the base and screen units, and base support height) and the workstation (heights of seat support and footrest, and distance between the body and the NBC).

• 자원리싸이클링
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• 제2권4호
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• pp.23-26
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• 1993

This work is carried out to develop the recovery process of vanadium as vanadium pentoxide and nickel as nickel sulphate from the leaching solution of heavy oil fly ash. First, sodium chlorate solution was added to the leaching solution to oxidize vanadium ions. With adjusting pH of the solution and heating, vanadium ions(V) is hydrated and precipitated as red cake of $V_2O_5$ from the solution. After recovering vanadium, nickel is recovered as ammonium nickel sulfate with crystallization process. From this nickel salt, nickel sulfate which meets the specifications for the electroplating industry can be produced economically. More than 85% of vana-dium and nickel in the fly ash are recovered in this process.