• 전자공학회논문지
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• 제53권11호
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• pp.66-70
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• 2016

본 논문에서는 심장박동 측정 레이더 송수신기용 24 GHz I/Q 발생기를 제안한다. 공정 변화에 따른 I/Q LO 신호간의 부정합 특성을 개선하기 위하여 인덕터와 캐패시터로 구성된 high-pass 위상천이기와 low-pass 위상천이기 기반 24 GHz I/Q LO 발생기를 제안하였다. 제안한 24 GHz I/Q 발생기는 LO 버퍼와 high-pass 위상천이기와 low-pass 위상천이기 구성된 24 GHz I/Q LO 발생기는 65 nm CMOS 공정에서 설계되었고, 전원 전압 1 V에서 8 mA의 전류를 소모하면서 24.05 GHz에서 24.25 GHz의 주파수 대역에서 7.5 dB의 전압 이득, 2.3 dB의 잡음 지수, 공정 및 온도 변화에 대해 0.1 dB의 I/Q 이득 부정합, 4.3도의 I/Q 위상 부정합의 성능을 보인다.

• 한국항행학회논문지
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• 제13권1호
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• pp.41-47
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• 2009

이 논문에서는 마이크로스트립을 이용하여 차단주파수가 10.2 GHz인 계단형 임피던스 구조의 저역 통과 여파기를 설계하고, 차단주파수 3.2 GHz인 병렬 스터브를 이용한 고역 통과 여파기를 설계하여 서로 결합하고 삽입하여 소형화하는 방식으로 UWB 대역을 포함하는 대역통과여파기를 설계, 제작하였다. 설계에 사용된 기판의 유전율은 2.2, 높이 0.508mm, loss tangent 0.0009이고, 대역통과 여파기의 넓이는 약 3 cm의 소형으로 제작되었다. 통과 대역에서의 측정 결과 -10 dB 대역폭은 7.5 GHz, -3dB 이하의 삽입손실의 특성을 보였다. 이 연구의 결과 UWB 통신 시스템과 MIC/MMIC, RFIC 시스템에 충분히 이용될 수 있을 것이다.

• 대한전자공학회논문지TC
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• 제46권9호
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• pp.60-65
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• 2009

본 논문에서는 대역통과 여파기와 대역저지 여파기를 하나의 구조로 합성하여 크기 증가 없이 초광대역 특성을 가지면서 Wireless-LAN 대역을 저지하는 대역통과 여파기를 설계, 구현하였다. 대역저지 특성을 얻으면서도 여파기의 크기증가가 없어야 하기 때문에 전송선에 내장된 형태의 오픈 스터브를 사용하였다. 그리고 저역 통과 특성을 얻기 위하여 접지 면에 식각할 수 있는 DGS(Defected Ground Structure) 구조를 이용하였다. 기존의 대역통과 여파기와 저역통과 여파기를 직접 연결하였을 때 보다 크기를 줄일 수 있었다. 측정결과 통과대역은 $2.21GHz{\sim}10.92GHz$ 이고 삽입손실은 최대 0.7dB, 반사손실은 최소 17dB, 군 지연 변화폭은 0.22ns였으며 $5.3GHz{\sim}5.7GHz$의 저지대역을 형성하였다.

• 한국조경학회지
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• 제33권4호
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• pp.22-32
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• 2005

The purpose of this study is to analyze characteristics of prospect from the mountain pass by investigating relations between the type of mountain pass and object overlooked from the mountain pass. For the purpose, this researcher selected and surveyed 44 mountain passes located in Busan, except in Gangseo-gu lesion. According to their locational characteristics, the mountain passes were classified into three types, 'sanmok'(formed between mountain peaks), 'sanheori'(formed on the mountainside) and 'sanmaru'(formed at the tip of the mountain peak). Out of the total 44 mountain passes, 22 were 'sanheori' in type. In the same type, mountain passes mostly had a prospect providing the overlap of downtown and mountain areas. The researcher examined the sight distance and dip of object to be viewed from the mountain pass, determining relations between the object and the mountain pass. When overlooked from mountain passes in Busan, most objects are distributed between $-3^{\circ}\;and\;-1^{\circ}$ in an angle of depression within the sight distance from 0.5km to 14km. Mountain passes are valuable as a post that is very important in prospecting scenes. But they are now in crisis. They are being gradually disappeared because of development projects. Finally, the researcher hopes that the study makes recognizing the value of the mountain pass and contributes to preserve the mountain pass as an important post of view point when its region is later developed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.78-81
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• 2000

A new type low-pass filter design method based on a coupled line and transmission line theory is proposed to suppress harmonics by attenuation poles in the stop band The design formula are derived using the equivalent circuit of a coupled transmission line. The new low-pass filter structure is shown to have attractive properties such as compact size, wide stop band range and low insertion loss. The seventh-order low-pass filter designed by present method Ins a cutoff frequency of 0.9 GHz with a 0.01 dB ripple level. The coupled line type low-pass filter with stripline configuration was fabricated by using a high-temperature superconducting (HTS ; $YBa_2Cu_3O_{7-x}$) thin film on MgO(100) substrate. Since the HTS coupled line type low-pass filter was proposed with five attenuation poles in stop band such as 1.8, 2.5, 4, 5.5, 62 GHz. The fabricated low-pass filter has improved the attenuation characteristics up to seven times of the cutoff frequency Bemuse of good rejection of the spurious signals and harmonics, our low-pass filter is applicable to mobile base station systems such as cellular, personal communication systems and international mobile telecommunication(IMT)-2000 systems.

• Journal of Welding and Joining
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• 제28권4호
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• pp.26-32
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• 2010

The purpose of this study is to evaluate the residual stresses at the multi-pass FCA weldment using the finite element analysis (FEA). In order to do it, an H-type specimen was selected as a test specimen. The variable used was in-plane restraint intensity. The temperature distribution at the multi-pass FCA butt weldment was evaluated in accordance with the relevant guidance recommended by the KWJS. The effective conductivity for the weld metal corresponding to each welding pass was introduced to control the maximum temperature below the vaporization temperature of weld metal. The heat flux caused by welding arc was assumed to be applied to the weld metal corresponding to welding pass. With heat transfer analysis results, the distribution of transverse residual stresses was evaluated using the thermo-mechanical analysis and compared with the measured results by XRD and uniaxial strain gage. In thermo-mechanical analysis, the plastic strain resetting at the temperature above melting temperature of $1450^{\circ}C$ was considered and the weld metal and base metal was assumed to be bilinear kinematics hardening continuum. According to the comparison between FEA and experiment, transverse residual stresses at the multi-pass FCA butt weldment obtained by FEA had a good agreement with the measured results, regardless of in-plane rigidity. Based on the results, it was concluded that thermo-mechanical FE analysis based on temperature distribution calculated in accordance with the KWJS’s guidance could be used as a tool to predict the distribution of residual stress of the multi-pass FCA butt weldment.

• 대한전자공학회논문지TC
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• 제49권7호
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• pp.65-70
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• 2012

본 논문은 CRLH와 DGS 구조를 합성하여 초광대역 대역 통과 특성이 있으면서 통과대역 내에 조정가능한 이중대역 저지 기능이 있는 필터를 제안한다. 초광대역 대역통과 여파기는 WLAN과의 전파간섭을 피하기 위해 2.4GHz와 5.8GHz를 저지하여야 한다. 이를 위해 본 논문에서는 CRLH구조를 이용하여 2중 저지 대역을 형성하였으며 통과 대역 이후 주파수에서 우수한 대역 저지 효과를 얻기 위해 DGS구조를 합성하였다. 실제 제작된 여파기 측정결과 2.4GHz와 5.8GHz에서 30dB 이상의 저지 특성을 확인하였다. 차단 주파수는 CRLH의 파라미터를 변경함으로써 매우 쉽게 이루어질 수 있다. 제작된 여파기는 0.4dB(Lower Pass-Band), 0.7dB(Upper Pass-Band)의 삽입손실과 0.6ns 이하의 작은 Group Delay를 확인하였다. 또한 크기가 17mm*17mm 로 매우 소형이다.

• 무역학회지
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• 제45권2호
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• pp.1-16
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• 2020

Korea is one of active countries in terms of FTA(Free Trade Agreement) around the globe. Local market is not big enough for Korean companies. This is why Korea is actively participating in FTA with various countries. Individual companies should conform to regulation, policy and system relevant to the agreement. Otherwise, it is not easy for companies to enjoy benefits of FTA. The Korean government is using various FTA programs to support domestic companies, in particular SMEs(Small and Medium-Sized Enterprises). FTA-PASS is a representative program. FTA-PASS is an official program of Korea Customs Service. Korean companies can use the program as free. However, some companies may have difficulties regarding the use of FTA-PASS. The program may cause of compatibility problem related their own ERP(Enterprise Resource Planning) systems. This study is designed to analyze determinants of FTA-PASS and ERP system compatibility. Furthermore this study aims to examine effects of the system compatibility on export performances. This study collected data from Koreas SMEs. In specific, the primary data was based on surveys distributed to 303 SMEs. Based on empirical findings, we could get important determinants to improve compatibility between FTA-PASS and ERP systems. For instance, the government support, product standardization, HS Code clearness and market stability could be considered important determinants. Also, according to empirical findings, a positive relationship between system compatibility an export performance was supported. Analyzing comprehensive determinants of system compatibility can be suggested as an important topic for future research.

• 한국세라믹학회지
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• 제36권6호
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• pp.618-624
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• 1999

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.91-92
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• 2009