• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.11a
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• pp.65-70
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• 2001

우리 나라의 온실 설치 면적은 1999년말 현재 51,200ha에 이르고 있으며 그 중 유리온실이 363ha로 0.7%, 철골 경질판 온실이 125ha로 0.2%이고, 아연도강관을 사용한 비닐하우스가 50,712ha로 99.1%를 차지하고 있다. 파이프 골조의 비닐하우스는 대부분 아치형의 지붕 모양을 하고 있으며, 바람에는 비교적 강하나 적설에 약한 구조이다. 전국적으로 가장 널리 분포하고 있는 직경 25.4mm, 두께 1.5mm의 파이프를 사용한 폭 6m의 단동 온실의 경우 서까래 간격 60~80cm일 때 안전 적설심은 10~14cm 정도에 불과하다(남 등, 2000). (중략)

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.12-14
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• 2008

부하가 밀집된 도심지의 배전전주는 고저압 배전선로용은 물론 주상변압기, 개폐기 등 배전기기의 설치를 위하여 필요불가결한 설비 중의 하나이다. 그러나 도심지에서는 미관저해 및 건물의 가치하락을 우려하는 민원으로 인하여 신규 건주에 어려움을 쥐고 있다. 본 연구에서는 이러한 문제점을 해결하고자 일반전주의 2배인 최대 6대의 주상변압기, 2대의 개폐기 및 특고압 인입설비를 설치할 수 있도록 2개의 상부 구조를 가지는 Y형 강관전주를 개발하였다.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.419-422
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• 2007

This paper, designed UWB elliptical slot antenna and analysis based on the distribution of the electromagnetic fields pattern and resonant mode of designed antenna is presented. Designed antenna is fabricated on FR4 substrate with thickness of 1.524mm and relative dielectric constant 4.4. The measured bandwidth of $3.6GHz{\sim}20GHz$ for VSWR<2. Through the field pattern and resonant mode analysis that the slot antenna operates on a series of the multi-pole radiation based on TE modes matched to system impedance. And the perfect magnetic wall is along the axis of symmetry on the y-z plane. This result gives us an easier method to design the similar antennas, which is the impedance matching to the system impedance after once constructing a proper structure with a series of multi-mode resonances.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.6
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• pp.636-643
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• 1999

본 논문에서는 기계 공구가 설계된 표면에 접근할 수 있는 모든 방향을 결정하는 기계가 공성 문제를 고려한다. 먼저 공구가 이동할 수 있는 자유도에 따라 여러 가지로 나뉘어지는 기계기공성 문제는 원으로 경계지워진 구상의 영역에 주어진 점의 집합을 포함하는가 결정하는 일원화된 문제로 형식화된다. 공구의 특성과 이동자유도를 반영한 구상의 영역을 도메인이라 한다. 도메인중에 대표적인 경우는 소디스크(small disk)와 대밴드(great band)이다. 우리는 이 두가지 경우에 주어진 점의 집합을 포함하는 모든 도메인의 극(pole)을 구하는 O(nlogn)시간의 알고리즘을 제시한다. 여기서 n은 가공할 면으로부터 사상된 구상의 점의개수이다.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.219-223
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• 2004

Since rotor position information is necessary to drive the SRM, absolute-encoder, resolver and incremental encoder is used to detect a rotor position. But, it is not desirable to use a high price encoder and microprocessor under the condition of the simple driving system when precision control is not demanded. In this paper, only using the reflective type two photo-sensors replaces the conventional opto-interrupter and slotted-disk, which not only remove a slotted-disk section but drive three-phase 6/4 pole SRM bidirectionally, Therefore, control circuit can compose common analog device with low price.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.371-379
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• 2000

The 4-pole linear homopolar synchronous motor (LHSM), so called linear inductor motor, is composed of the figure-of-eight shaped 3-phase armature windings, DC field windings, and the segmented secondary with the transverse bar track. To reduce the calculation time, the simplified 3D finite element model with equivalent reluctance and/or permanent magnet is presented. To obtain a clear understanding, propriety and usefulness of the developed model, we compare with the results of simplified 3D FEA, general 3D FEA and test. Consequently, the results of simplified and 3D FEM analysis are nearly identical, but much larger than that of static test at d-axis armature excitation. Therefore the improved FEA model, such as full model with half slot, is needed for the precise analysis.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.6-8
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• 2001

We evaluated the degree of texture through depth of the superconductor core of Bi-Sr-Ca-Cu-O(BSCCO) superconductor tape. The degree of texture was characterized by pole figure analysis, indicating that the degree of texture varied significantly with depth of the superconductor core. It was observed that the degree of texture was higher near the interface than inside the superconducting core. Based on the result of degree of texture, the region near the interface is thought to carry significant current compared to that inside the core.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.196-201
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• 2008

This paper is about electromagnetic vibration source in outer rotor type of BLDC motors. Experiments are carried out with three pole-slot combinations which are 6 slots, 12 slots, and 24 slots with 4 poles rotor. According to results, vibration sources separate into electromagnetic and mechanical factors. Using the finite element method (FEM), It is analyed that vibration characteristics of electromagnetic source in each type. This paper shows electromagnetic sensitivity to vibration, and introduces necessary point in lower vibration motors. Also rotor balance is important to prevent uneven distribution of magnetic flux between rotor and stator.

• The Korean Journal of Ceramics
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• v.3 no.4
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• pp.253-256
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• 1997

Epitaxially grown Pb(Zr, Ti)O$_3$thin films were prepared on LaAlO$_3$substrates by the dipping pyrolysis process using metal naphthenates as starting materials Homogeneous Pb-Zr-Ti solutions with toluene were spin-coated onto the substrates and pyrolyzed at 50$0^{\circ}C$ Highly oriented Pb(Zr, Ti)O$_3$films confirmed by X-ray diffraction $\theta$-2$\theta$ scans were obtained by heat-treated at 75$0^{\circ}C$ in air The X-ray pole-figure analysis and reciprocal-space mapping of the resulting 0.6$\mu\textrm{m}$ films showed that the thin films comprising the c-axis oriented tetragonal phase have an epitaxial relationship with the LaAlO$_3$substrates.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.6
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• pp.342-350
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• 2003

In this paper, a levitation controller for a magnetic levitation(MagLev) system is designed and implemented. The target to be controlled is PEM(permanent and electromagnet) type with 4-corners levitation which is open-loop unstable, highly non-linear and time-varying system. The digital control system consists of a VME-based CPU board, AD board, PU board, 4-Quadrant chopper, and gap sensor, accelerometer as feedback sensors. In order to estimate the velocity of the magnet, we used 2nd-order state observer with acceleration and gap signal as input and output, respectively. Using the estimated states, a state feedback control law for the plant is designed and the feedback gains are selected by using the pole-placement method. The designed controller is experimentally validated by step-type gap reference change and force disturbance test.