• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.4
• /
• pp.611-621
• /
• 2001

This paper presents a design methodology of bandpass filter by using defect modes in photonic bandgap (PBG) structures. PBG structures are realized with alternating section of microstrip line arranged in a periodical manner. A passband is created within the stopband of PBG structures with defect modes, which can be generated by changing the period of certain part of PBG structure. We also extract a simple equivalent circuit of a bandstop filter by using several LC sections.

• Sleep Medicine and Psychophysiology
• /
• v.11 no.1
• /
• pp.5-9
• /
• 2004

Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent cessation of breathing due to complete or partial upper airway occlusion during sleep. The incompetent tone of palatal, pharngeal, and glossal muscles which fail to maintain airway patency during sleep causes narrowing of the airway dimension and increased resistance of breathing. The identification of the sites of upper airway obstruction in patients with OSA is important in understanding the pathogenesis and deciding the treatment modality of snoring and/or OSA. Various upper airway imaging modalities have been used to assess upper airway size and precise localization of the sites of upper airway obstruction during sleep. Dynamic imaging modalities enabled assessment of dimensional changes in the upper airway during respiration and sleep. This article focused on reviews of various upper airway imaging modalities, especially dynamic upper airway imaging studies providing important information on the pathogenesis of OSA.

• Journal of the Korean Society of Safety
• /
• v.16 no.3
• /
• pp.12-18
• /
• 2001

The objective of the present work is to examine the effect of inclined angle of channel with multi heat source on thermal stability of electronic equipment. The heat sources are mounted on both sides of channel walls by two kinds of configuration such as the zig-zag md symmetric on. Conductive heat transfer was estimated by using of thermocouples and heat flux sensor. Thus, convective heat transfer and mean Nusselt number could be obtained. With increased inclined angle, the convective heat transfer coefficient was decreased. When inclined angle was smaller than 30 degree, The average Nusselt number of Big-zag configuration was larger than that of symmetric. Furthermore, when protruding ration was 0.082, the temperature was strongly affected by inclined angle. whereas, when protruding ration was 0.25, the temperature was strongly affected by heat source configuration.

• Proceedings of the KIEE Conference
• /
• 2007.10a
• /
• pp.83-84
• /
• 2007

작업자가 작업장에서 전도 등으로 인한 산업 재해를 입지 않도록 하기 위해서는 작업장에서의 전도 상황을 판단하여야 하며, 이러한 전도 상황을 측정할 때 자동화된 전도 측정 장치는 작업장에서의 효율성을 확보하는 동시에, 전도를 측정하는 사람이 측정 과정예서 일어날 수 있는 불상사 등을 예방하여 산업재해를 미연에 방지해서 이를 통한 산업 현장의 안정성 확보를 통한 부대 비용 발생을 방지할 수 있게 된다. 이러한 자동화된 전도 측정을 위한 방편으로써 전도 측정용 로봇의 개발하였다.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.243-247
• /
• 2005

본 논문에서는 영구자석 동기전동기의 운전중 간섭성분을 형성하는 고정자 인덕턴스가 변화할 경우 d축 전류의 오차로부터 고정자 인덕턴스의 변화량을 보상할 수 있는 보상기를 제안하였다. 그리고 이러한 보상기를 기존의 DDC(Dynamic Decoupling g Control)에 적용하여, 고정자 인덕턴스의 변화에 대한 강인성이 향상된 비간섭 전류제어기를 설계하였다.

• 전기의세계
• /
• v.25 no.2
• /
• pp.100-106
• /
• 1976

A comparative study on thermal, static mechanical and dielectric characteristics were made over a temperature range of ca.20.deg.C to 320.deg.C and a frequency range of KHZ to MHZ band on low density polyethylene specimens crosslinked, respectively, by radiation and chemical method. The thermal property of both specimens shows that softening point appears to unchange by crosslinking, however, melting and liquidizing temperatures attain rapid increase at the imitiation of crosslinking. Mechanical properties show little difference to both specimens crosslinked by different method, further the behaviors were discussed in connection with the relaxation of molecular segments in amorphous phase. Dose dependent dielectric characteristics observed at ambient temperature under several fixed frequencies exhibit extremities at ca. 20 Mrad and the behaviors also were interpreted qualitatively by taking into consideration of dipole concentration change in amorphous phase together with the role of specimen geometry to the depth of oxidative layer. Observing frequency dependent dielectric characteristics, it was also proved that ionic conduction loss is appreciably greater in the specimen prepared by chemical method than that by radiation.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2016.04a
• /
• pp.879-882
• /
• 2016

본 논문은 인공암벽에 부착된 홀드의 형태 및 위치 인식 시스템을 제안한다. 스크린 클라이밍 시스템에 있어서 인공암벽에 부착된 홀드의 형태와 위치 데이터는 다양한 정보로 활용되지만 사람이 수작업으로 계산하기에는 어려움이 따른다. 홀드의 형태가 각기 다르며, 인공암벽에 부착된 홀드의 수가 보통 수백 개 이상 되기 때문이다. 따라서 제안하는 인식 기술을 통하여 자동으로 홀드의 형태와 위치 데이터를 계산할 수 있게 한다. 홀드의 형태는 스네이크 알고리즘으로 윤곽선을 추출해 인식하며, 홀드의 위치는 추출된 윤곽 데이터의 무게중심 점을 계산하여 인식한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.06a
• /
• pp.253-257
• /
• 1998

Organic-based electroluminescent devices have attracted lots of interests because of their possible application as large-area flat pan디 display. In this study, current-voltage (I-V) characteristics of MEH-PPV thin films was investigated using various metal as a top electrode, where MEH-PPV thin films were prepared on 170 substrate by spin coating method and various metal such as Al, Ag, In, MgIn was deposited on MEH-PPV thin films as a top electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.609-612
• /
• 1999

Organic electroluminescent(EL) devices have received a great deal of attention due to their potential application as full-color displays. They are attractive because of their capability of multicolor emission, ease of fabrication, and operation at a low driving voltage. In this study, single and multiple quantum-well structures consisting of Eu(TTA)$_3$(bpy) complex well layer sandwiched between triphenyldiamine derivative (TPD) layers were fabricated and their photoluminescent electroluminescent characteristics were also investigated. Sharp emission at 616 nm has been observed from the Eu complex in multilayer, single and multiple quantum-well structures. Details on the explanation of electrical properties of these structures will be discussed.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.1754-1756
• /
• 2000

Organic semiconductors based on fused-ring polycyclic aromatic hydrocarbon have great potential to be utilized as an active layer for electronic and optoelectronic devices. In this study, pentacene thin films and electrode materials were deposited by Organic Molecular Beam Deposition(OMBD) and vacuum evaporation respectively. For the gate dielectric, polyamic acid was spin-coated and cured into polyimide at 350$^{\circ}C$. Electrical characteristics of the devices were investigated, where the channel length and width was 50${\mu}m$ and 5mm. It was found that field effect mobility was 0.012$cm^{2}/Vs$, and on/off current ratio was $10^5$.