• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.184-188
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• 1999

Switched Reluctance Motor has doubly salient poles in stator and rotor, windings are wound in just stator and no magnet or windings on the rotor. This configuration is robust mechanically and thermally. The inverter of SRM is more robust than that of induction or brushless DC(BLDC) motor, but still its drive is comparatively expensive for home appliance. To drive the conventional three or four-phase SRM, 6 to 8 power switches are required when asymmetric bridge inverter is employed. Generally, more than 50% of the cost for the SRM drive is allocated to power devices and gate drives. This paper proposed single phase SRM that have both radial and axial air gaps. The stator and rotor were stacked with two types of stampings that have different diameters. This configuration is very effective to increase align inductance(Lmax). The high value of Lmax increases the motor efficiency and power density. The proposed single phase SRM(Claw SRM) can be driven by only two power switches. To show the validity of the proposed idea, the analysis using finite element method(FEM) and experimental works are carried out. The proposed SPSRM can be driven with high efficiency and can be made compactly and inexpensively because of high value of align inductance and less number of switches. For the comparison, we used same stator for three-phase and single phase, and slightly different stator and rotor for proposed single phase SRM(Claw SRM)

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.379-385
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• 2018

Boresight process is to match the misalignment between PNU(Position Navigation Unit) and the reference axis of K-MLRS cage. It is important process to ensure accuracy of K-MLRS. When PNU is removed from cage in the previous alignment procedure, there is a misalignment angle with cage of K-MLRS during reassembly process. Therefore, boresight process is always need to align reference axes between PNU and K-MLRS cage. However, this study has proposed the case alignment process that it enable to correspond to reference axes between ISA (Inertial Sensor Assembly) block and PNU case. So, improved alignment procedure enables to install PNU in the reassembly process without additional boresight process.

• The Journal of Korea Robotics Society
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• v.12 no.4
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• pp.411-418
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• 2017

During the intramedullary nailing procedure, surgeons feel difficulty in manipulation of the X-ray device to align it to axes of nailing holes and suffer from the large radiation exposure from the X-ray device. These problems are caused by the fact the surgeon cannot see the hole's location directly and should use the X-ray device to find the hole's location and direction. In this paper, we proposed the robotic guidance of the distal screwing using an optical tracking system. To track the location of the hole for the distal screwing, the reference marker is attached to the proximal end of an intramedullary nail. To guide the drill's direction robustly, the 6-degree-of-freedom robotic arm is used. The robotic arm is controlled so as to align the drill guiding tool attached the robotic arm with the obtained the hole's location. For the safety, the robot's linear and angular velocities are restricted to the predefined values. The experimental results using the artificial bones showed that the position error and the orientation error were 0.91 mm and $1.64^{\circ}$, respectively. The proposed method is simple and easy to implement, thus it is expected to be adopted easily while reducing the radiation exposure significantly.

• Journal of Information Display
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• v.4 no.2
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• pp.29-34
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• 2003

We have studied liquid crystal (LC) molecular alignment on rubbed and photoaligned surfaces. Particular attention was paid to the intermolecular liquid crystalline interaction. We will first show that uniform molecular orientation on a rubbed surface does not mean spatially uniform interaction between the surface and LC molecules. Rather LCs tend to align themselves through LC interaction. The existence of nonuniformity of rubbing was successfully visualized by double surface treatment. The importance of intermolecular LC interaction was also found in the orientation formation process in 5CB evaporated on rubbed and photoaligned surfaces. By simultaneously analyzing polarized UVNIS absorption and second-harmonic generation (SHG) using the maximum entropy method, we succeeded in obtaining the temporal variation of the orientational distribution functions in the film forming process. The distribution anisotropy and pretilt are found to be generated under the influence of intermolecular LC interaction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.173-176
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• 2005

Teijin사의 HT100-B60의 폴리카보네이트(polycarbonate) $100{\mu}m$, I-Component사의 PES(polyethersulfone) $200{\mu}m$, Ferrania사의 PAR(polyacrylate) $100{\mu}m$와 $200{\mu}m$를 사용하였다 열팽창계수의 차이로 인해 공정상 기판의 가열과 냉각시 열응력이 발생하여 기판의 크랙발생의 원인이 된다. 이를 최소화하기 위해 모든 공정이 시작하기 전에 pre-annealing을 통해 plastic 기판의 시간별 공정을 실시하였다. plastic film의 annealing time은 0h, 12h, 24, 40h, 50h, 60h, 70h, 80h으로 사간을 달리하여 오븐 안의 진공상태를 조성하여 실험하였다. Thermal evaporator로 Al을 약 170nm 증착하였으며 (주)동진 세미캠의 DTFR-1011s DR LCD용 감광액을 Spin Coating Spread(500rpm/6sec), Spin(3000rpm/20sec)으로 coating하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.162-162
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• 1999

초고주파 집적회로의 핵심소자로 각광을 받고 있는 GaAs MESFET(MEtal-emiconductor)은 게이트 형성 공정이 가장 중요하며, WNx 내화금속을 이용한 planar 게이트 구조의 경우 임계전압(Vth:threshold voltage)의 균일도가 우수할 뿐만 아니라 특히 Side-wall을 이용한 self-align 게이트는 소오스 저항을 줄일 수 있어 고성능의 소자 제작을 가능하게 한다.(1) 본 연구의 핵심이 되는 Side-wall을 형성하기 위하여 PECVD법에 의한 SiOx 박막을 증착하고, 건식식각법을 이용하여 SiOx side-wall을 형성하였다. 이 공정을 이용하여 소오스 저항이 낮고 임계전압의 균일도가 우수한 고성능의 self-aligned gate MESFET을 제작하였다. 3inch GaAs 기판상에 이온주입법에 의한 채널 형성, d.c. 스퍼터링법에 의한 WNx 증착, PECVD법에 의한 SiOx 증착, MERIE(Magnetic Enhanced Reactive Ion Etcing)에 의한 Side-wall 형성, LDD(Lightly Doped Drain)와 N+ 이온주입, 그리고 RTA(Rapid Thermal Annealing)를 사용하여 활성화 공정을 수행하였다. 채널은 40keV, 4312/cm2로, LDD는 50keV, 8e12/cm2로 이온주입하였고, 4000A의 SiOx를 증착한 후 2500A의 Side-wall을 형성하였다. 옴익 접촉은 AuGe/Ni/Au 합금을 이용하였고, 소자의 최종 Passivation은 SiNx 박막을 이용하였다. 제작된 소자의 전기적 특성은 hp4145B parameter analyzer를 이용한 전압-전류 측정을 통하여 평가하였다. Side-wall 형성은 0.3$\mu\textrm{m}$ 이상의 패턴크기에서 수직으로 잘 형성되었고, 본 연궁에서는 게이트 길이가 0.5$\mu\textrm{m}$인 MESFET을 제작하였다. d.c. 특성 측정 결과 Vds=2.0V에서 임계전압은 -0.78V, 트랜스컨덕턴스는 354mS/mm, 그리고 포화전류는 171mA/mm로 평가되었다. 특히 본 연구에서 개발된 트랜지스터의 게이트 전압 변화에 따른 균일한 트랜스 컨덕턴스의 특성은 RF 소자로 사용할 때 마이크로 웨이브의 왜곡특성을 없애주기 때문에 균일한 신호의 전달을 가능하게 한다. 0.5$\mu\textrm{m}$$\times$100$\mu\textrm{m}$ 게이트 MESFET을 이용한 S-parameter 측정과 Curve fitting 으로부터 차단주파수 fT는 40GHz 이상으로 평가되었고, 특히 균일한 트랜스컨덕턴스의 경향과 함께 차단주파수 역시 게이트 바이어스, 즉 소오스-드레스인 전류의 변화에 따라 균일한 값을 보였다. 본 연구에서 개발된 Side-wall 공정은 게이트 길이가 0.3$\mu\textrm{m}$까지 작은 경우에도 사용가능하며, WNx self-align gate MEESFET은 낮은 소오스저항, 균일한 임계전압 특성, 그리고 높고 균일한 트랜스 컨덕턴스 특성으로 HHP(Hend-Held Phone) 및 PCS(Personal communication System)와 같은 이동 통신용 단말기의 MMICs(Monolithic Microwave Integrates Circuits)의 제작에 활용될 것으로 기대된다.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.169-170
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• 2009

We present a quantification protocol to get the alignment factors of a custom-made spectrometer and the nonlinear fitting function between the measured CCD pixel domain and the wavelength domain to apply the spectral-domain optical coherence tomography using fiber Bragg gratings. We have used 4 different center wavelength gratings with a narrow spectral bandwidth (<0.05 nm) and the same reflectivity (>92 %) to calibrate and align the custom-made spectrometer.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.167-170
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• 2004

This paper proposes resource allocation method for achieving investment goals in manufacturing system. In order to align resource allocation and manufacturing system design, the system design decomposition (SDD) approach is used. In this paper, a mathematical formulation for resource allocation based on SDD approach is analyzed and a genetic algorithm application is discussed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.87-90
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• 2001

One of the most important challenges facing companies in the age of internet business is the proper alignment customers needs with internet business system that allaws them to react rapidly and continuously. This paper proposes a methodo1ogy to align analyzing customer's requirements with implementing Internet business system The methodology consists of five Phases. It covers from customer analysis to Internet business system implementation, and each of the five phases has its own activities and outputs. A real- world case is proposed to illustrate the application of the methodology.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.981-986
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• 1993

A fast algorithm based upon geometry to measure the wafer center and the position of a wafer fiducial mark is developed and implemented on a single-axis aligner. Design issues for a controller when a National Semiconductor's LM629 is used as a PID controller of an aligner are discussed. Performance of an aligner with the algorithm and a LM629 was measured in experiments. The result shows that it takes about 4.1 seconds on average to align a hot wafer supported by metal pins on the chuck.