• ETRI Journal
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• 제35권3호
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• pp.361-370
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• 2013

In this paper, a packet-reduced ranging method using a superresolution time of arrival estimation algorithm for a chirp-based real-time locating system is presented. A variety of ranging methods, such as symmetric double-sided two-way ranging (SDS-TWR), have been proposed to remove the time drift due to the frequency offset using extra ranging packets. Our proposed method can perform robust ranging against the frequency offset using only two ranging packets while maintaining almost the same ranging accuracy as them. To verify the effectiveness of our proposed algorithm, the error performance of our proposed ranging method is analyzed and compared with others. The total ranging performance of TWR, SDS-TWR, and our proposed TWR are analyzed and verified through simulations in additive white Gaussian noise and multipath channels in the presence of the frequency offset.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권4호
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• pp.394-398
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• 2013

This paper presents output characteristics of a linear switched reluctance motor (LSRM) with excitation windings wound by using high-temperature superconducting (HTS) tapes. In a double-sided LSRM, Bi-2223 or YBCO tape conductors are used for the excitation windings. The characteristics of the LSRM are obtained by a finite element method analysis. We can obtain large thrust compared with a conventional LSRM by using YBCO tape conductors. Also, the effect of a configuration of the YBCO coil on the thrust is calculated. We discuss a suitable coil configuration for the average thrust upgrading.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.123-128
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• 2002

Over the range(OTR) has been applied for cooking and ventilation functions especially in northern Amarica. Because flow rate and operating rpm of the double sided sirocco fan for ventilation are much higher and than the microwave oven system, the major noise source is the sirocco fm. Recently, the quiet fan development is one of very important issues for amenity. In this study, the noise source identification using multi-microphone array system was carefully carried out and numerical simulations for understanding the aerodynamic and aeroacoustic of the fan were peformed. The sound level of tonal noise is predicted with a good accuracy but that of the broadband shows some discrepancy. In order to reduce the broadband noise, the inlet region of sirocco fan have to be modified that the secondary flow should be suppressed. Based on these results, new low noise fan and OTR is now developing.

• 공학교육연구
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• 제13권5호
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• pp.76-80
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• 2010

In this paper, the Location Compensation Mechanism using equivalent distance rate ($LCM_{edr}$) for localization system based on SDS-TWR (Symmetric Double-Sided Two-Way Ranging) in wireless sensor network is proposed. The performance of the mechanism is experimented in terms of two types of the localization tracking scenarios of indoor and outdoor environments in university campus. From the experimentations, the compensation ratio in the $LCM_{edr}$ is better than that in SDS-TWR about 90% in indoor/outdoor environments in scenario 1 but also is better than that of SDS-TWR about 91.7% in indoor environment and about 100% in outdoor environment in scenario 2 respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1210-1211
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• 2011

The inherent drawback of iron-core type permanent magnet linear synchronous motor (PMLSM) is detent force that is dependent on several major factors such as PM length, slot clearance, and skewing. To minimize the detent force, this paper proposes a structure optimization using the combination computation of two dimensional (2-D) finite element analysis (FEA) and response surface methodology (RSM). The RSM, that is a collection of the statistical and mathematical techniques, is utilized to predict the global optimal solution based on the FEA calculated results of the detect forces for different combinations of factors. With the help of the combination computation the high capacity iron-core type PMLSM with more than 12000 N propulsion forces only contains less than 3 N detent forces.

• Journal of Korean Neurosurgical Society
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• 제55권2호
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• pp.99-102
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• 2014

A previously healthy 52-year-old man presented to the emergency room with acute onset left hemiparesis and dysarthria. Brain computed tomography and magnetic resonance examinations revealed acute cerebral infarction in the right middle cerebral artery territory and a sphenoid ridge meningioma encasing the right carotid artery terminus. Cerebral angiography demonstrated complete occlusion of the right proximal M1 portion. A computed tomography perfusion study showed a wide area of perfusion-diffusion mismatch. Over the ensuing 48 hours, left sided weakness deteriorated despite medical treatment. Emergency extracranial-intracranial bypass was performed using a double-barrel technique, leaving the tumor as it was, and subsequently his neurological function was improved dramatically. We present a rare case of sphenoid ridge meningioma causing acute cerebral infarction as a result of middle cerebral artery compression.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.973.1_974.1
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• 2009

One of the most important technical improvement required for ropeless elevator system to become practical is the improvements in overall system efficiency. Moreover, the predominant drawback of permanent magnet (PM) linear synchronous motor (LSM) is large detent force. Therefore, for the given volume the selection of high power density PM-LSM with low detent force is very imperative. In this paper, we will investigate the characteristics of thrust and detent force of PM-LSM under different motor topology structure. Finally, the long stator double-sided iron core type PM-LSM with fractional slot winding is the best choice for the ropeless elevator system.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.107-111
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• 1999

A high-temperature superconducting 1.78 GHz bandpass filter, designed for PCS applications, is presented. The structure consists of microstrip pseudo-lumped elements, which make the miniaturization of the filter possible. A 5-pole microstrip filter can be realized on 37 mm ${\times}$ 9 mm LaAlO$_3$ substrate, using double-sided high-temperature superconducting YBa$_2Cu_3O_{7-{\delta}}$ thin film. This filter shows 0.7% fractional bandwidth, 0.3 dB insertion loss, and 12 dB return loss in the passband at 60 K.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.264-267
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• 1996

This paper is aimed to develop a very reliable method for automatic inspection of the solder joints on PCBS. There have been lots of previous works using vision technologies, but they can not be used for inspecting BGA, FCA or other newly used devices. Thus we adopt X-ray technologies for solder joint inspection. We put our attention on reconstructing the 3D shapes of solder joints since it gives us the most detailed information on quality of solder joints. Laminography principle is used to reject the interferences from neighboring parts or leads. To verify the effectiveness of laminography, a simulation study is performed in the case of a solder joints on double sided PCB using.

• 한국전자파학회논문지
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• 제14권9호
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• pp.919-923
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• 2003

본 논문에서는 마이크로스트립 대 CPW결합 구조를 이용하여 다양한 신호 정합회로에 사용되는 발룬을 제작 측정하였다. 측정 결과, 가용 주파수 2.44~4.33 GHz에서 삽입 손실의 차이는 0.2 dB 이내이고 위상 차이는 2.1$^{\circ}$ 이내로 나타났다. 따라서 제안된 발룬은 구조적 특성으로 인해 다양한 초고주파용 다층 회로에 사용되어 혼합기, 증폭기, 안테나의 급전부 등의 성능향상에 기여할 것으로 기대된다.