• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1071-1078
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• 2003

In this paper, the planar, compact, and broadband phased array antenna system for IMT-2000 applications has been investigated. Two methods far designing a low-cost and low-complex beam-farming network are proposed. First, a new compact and broadband phase shifter with continuously controlled phase bits is designed by using parallel coupled lines. Second, its equivalent phase delay line is suggested to be capable of replacing the complex phase shifter with a reference phase bit on a phased array antenna. For the purpose of achieving the broadband system, in addition to the broadband phase shifter, a wide-slot antenna with a ground reflector is utilized as an element antenna. Therefore, the phased array antenna system has achieved compact size, broad bandwidth, and wide steering angle, although it has low complexity and low fabrication cost. The 3${\times}$1 phased array antenna system has a compact size of 1.6 λ${\times}$ l.6 λ, which is the sufficient ground plane of the wide-slot antenna. Experimental results present that the S$\_$11/ has less than 15 dB within the band and its radiation patterns on an E-plane have the capability of steering an antenna beam from -29$^{\circ}$to +30$^{\circ}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.535-543
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• 2009

This paper describes a design for RFID(Radio Frequency Identification) tag antenna using license plate attached the vehicle bumper in 900 MHz band. The proposed tag antenna size which is located on upper center position of a vehicle license plate is 162.5${\times}$40${\times}$1 mm$^3$. A resonant frequency of design antenna and the bandwidth which has return loss of -10 dB below are 900 MHz and about 720 MHz(640${\sim}$1,360 MHz), respectively. The commercial chip impedance considered on design was 16- j131 ${\Omega}$ and the complex conjugate impedance of chip was used as input impedance of tag antenna. The measured return loss and radiation pattern were agreed well with the calculated results. The measured readable range of the proposed tag antenna designed on only the vehicle license plate was 11.5 m. Moreover, its range of the fabricated tag antenna that the license plate and the vehicle bumper were fixed by volt and nut was observed 10.4 m. These measured readable range showed about 5 m above far distance more than the average readable range of commercial tag antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.11-19
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• 2013

In this paper, we designed and implemented the planar monopole antenna using the coupling effect for the multi-band characteristic. A parasitic element for the multi-band characteristic based on a rectangular patch with single resonance is inserted. Spiral shaped parasitic element is used for minimizing the antenna size and obtaining the multi-resonance characteristic. The frequency characteristics are modified and optimized by varying specific parameters. By inserting an L-shaped resonator at both sides of the feed line which connected through the via hole to the ground plane, unnecessary frequency bands are eliminated. Proposed antenna dimension is $40{\times}60{\times}1mm^3$. It is fabricated on the FR-4 substrate(${\varepsilon}_r$=4.4) using a microstrip line of $50{\Omega}$ for impedance matching. By measurement results, the characteristic of the return loss under -10 dB are 1.714~2.496 GHz, 2.977~4.301 GHz, and 4.721~6.315 GHz, and the radiation patterns have omni-directional shapes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.706-713
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• 2010

In this paper, the small loop antenna with a parasitic loop structure for penta-band mobile phone application is proposed. This antenna is composed of a feed monopole, a radiating loop antenna with a parasitic loop structure and an additional radiating element. The antenna is printed on the very thin flexible substrate to mount on the dielectric carrier with a volume of 40 mm$\times$11 mm$\times$3 mm. The bandwidth of the proposed antenna is 402 MHz(773~1,175 MHz) for low band and 583 MHz(1,622~2,205 MHz) for high band. As a result, the proposed antenna covers the five bands of GSM850, GSM900, DCS1800, PCS1,900 and WCDMA for a 3:1 VSWR. Moreover, the radiation pattern, gain and efficiency are appropriate for mobile handset. Therefore, this antenna is suitable for small sized multi-band mobile handset applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1754-1759
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• 2008

To produce plastic parts that have fine pattern through conventional injection molding, a lot of difficulties follow. Therefore, rapid heating and cooling methods are good candidates for manufacturing injection-molded parts with micro/nano patterns. In this study, we adopted the E-Mold patent technology. The mold for E-Mold technology has a separate heated core with micro heaters. It is very important to optimize the lay-out of the heaters in heated core because it influences both control and distribution of mold temperature. We developed a optimization method of heating line lay-out by using commercial softwares and compared the output with the experimental results. We used Pro-Engineer Wildfire 2.0 for the mold design, ICEMCFD for mesh generation, and FLUENT for heat transfer simulation. The simulation results showed the temperature profile from $60^{\circ}C$ to $120^{\circ}C$ or $180^{\circ}C$ during heating and cooling process which were compared with the injection molding experiments. We concluded that the simulation could well explain the experimental results. It was shown that the E-Mold optimization design for heater lay-out could be available through the simulation.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1194-1199
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• 2007

본 연구에서는 도시배수관망의 간략화 모의 시 지선을 단순 생략하는 것이 아니라 2차원 관망을 1차원으로 전환시키는 방법인 등가하천 개념을 도입하여 도시유역의 유출량 산정에 있어서 여러 지선들을 개별적으로 모의하지 않으면서도 실제 존재하는 지선들의 효과를 고려할 수 있는 방법을 개발하고자 하였다. 자연하천에 대해 개발된 등가하천 개념은 최근의 수문모형의 경향인 물리적 분포형 모형의 복잡성을 피하면서 전통적인 개념적 집중형 모형이 가지는 간편성을 살리고 그 것이 가지고 있는 선형가정의 한계를 극복하기 위한 방안으로서 제안된 방법이다. 등가하천 개념을 도입하여 개발된 모형은 종국적으로 강우-유출관계에 있어서 강우의 크기, 선형 및 비선형성, 유역면적 등이 미치는 영향을 분석하기위한 도구로 개발되었으며, 본 연구에서는 출구로부터 동일 거리 s에 위치한 지점에서의 배수관망의 공간적인 분포 및 집중패턴을 파악하는 폭함수(width function, n(s))와 면적함수(area function, M(s))를 이용하여 관망을 간략화 하였다. 등가관의 수리기하조건 결정은 유역이 정상상태에 도달했을 경우에 대해서 이루어지게 되며 정상상태 모의를 통해 개별 관망단면들에 대해 얻어진 유량(Q), 면적(A), 수심(y) 자료간의 상관관계를 유추하여 Q(A), A(y) 함수를 유도하게 되면 종국적으로 관로홍수추적에 이용되는 지배방정식의 매개변수인 파속계수(c) 및 확산계수(D)를 계산할 수 있게 된다. 본 연구에서는 대상 유역으로 군자 배수구역을 선정하여 유역의 특성과 관망 자료를 수집하고 간략화 기법을 적용한 결과를 분석 하였다.다. 21세기 문화산업에서 우리가 판단하게 될 디자인의 가치는 계몽의 원리에 대한 '역사성'과 '현재성'의 변증법에 달려있는 것이며, 새로운 철학, 새로운 문명, 새로운 세계를 열어가는 것이다.r$ (地理志)에는 추현리와 이미 외리를 언급하면서 상주의 자기제작의 위상을 짐작하는 기록이 언급되면서 전국의 상품의 절반을 담당하고 있었음을 알 수 있었다. $\ulcorner$경상도지리지$\lrcorner$(慶尙道地理志)에는 상주가 8곳으로 1/3의 자기 생산을 담당하고 있었다. $\ulcorner$경상도지리지$\lrcorner$(慶尙道地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와 동년대에 동일한 목적으로 찬술되었음을 알 수 있다. $\ulcorner$경상도실록지리지$\lrcorner$(慶尙道實錄地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기소의 위치가 완전히 삭제되어 있다. 이러한 현상은 첫째, 15세기

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.131-138
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• 2016

In this study, we tried to analyze the influence of ICM(Iodinated Contrast Media) in MR imaging compare to GBCA(Gadolinium Based Contrast Agent), and as this result we discussed whether resonable or not the protocol which is MRI scan after enhanced CT scan without proper time interval in clinical field. For this research, we assembled two phantoms. which one was iodine and another one was gadolinium. We did test two phantoms in conventional MRI scan which is T1, T2, T2 FLAIR and 3D angio. After that, quantitative analysis was progressed. The results of study were as follow : SSI(Saline's Signal Intensity) was shown as each sequences 175, 1231, 333, 37 [a.u] at iodine. and 1297, 123, 757, 232 [a.u] was recorded at gadolinium. BDEPS(the Biggest Difference of EPS) was shown as each sequences 1297, 123, 757, 232 [a.u] at iodine and 793, 6, 1495, 365 [a.u] was recorded at gadolinium. At this time, EPS(Enhancement Percentage to Saline) was shown 641.1, -90.0, 127.3, 527% at iodine and 685.1, 99.4, 365.7, 1077.4% was recorded at gadolinium. BP(BDEPS's point) was shown 900, 900, 477, 900 mmol at iodine and 4, 0.2, 0.2, 40 mmol was recorded at gadolinium. CPSS(Change Point of SI to SSI) was shown 63, 423, 63, 29 mmol at iodine and each [50, 30], [4, 0.2], [4, 1], 0.2 mmol was recorded at gadolinium. According to this research, we could not only discover the fact that was iodine could effect on MR signal, but also the pattern is different as various sequences compare to gadolinium. Therefore, we expect useful diagnostic MR image in clinical field with this quantitative data for deciding protocol regarding MRI and CT scan order.