• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.1-9
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• 2016

Train control systems have changed from wayside electricity-centric to onboard communications-centric. The latest train control system, the CBTC system, has high efficiency for interval control based on two-way radio communications between the onboard and wayside systems. However, since the wayside system is the center of control, the number of input trains to allow a wayside system is limited, and due to the cyclic-path control flows between onboard and wayside systems, headway improvement is limited. In this paper, we propose a train interval-control and train-centric distributed interlocking algorithm for an autonomous train-driving control system. Because an autonomous train-driving control system performs interval and branch control onboard, both tracks and switches are shared resources as well as semaphore elements. The proposed autonomous train-driving control performs train interval control via direct communication between trains or between trains and track-side apparatus, instead of relying on control commands from ground control systems. The proposed interlocking algorithm newly defines the semaphore scheme using a unique key for the shared resource, and a switch that is not accessed at the same time by the interlocking system within each train. The simulated results show the proposed autonomous train-driving control system improves interval control performance, and safe train control is possible with a simplified interlocking algorithm by comparing the proposed train-centric distributed interlocking algorithm and various types of interlock logic performed in existing interlocking systems.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.362-365
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• 2004

국간망과 가입자망의 초고속화가 이루어지더라도 구내망이 이를 뒷받침하지 않으면 초고속망 서비스의 제공은 이루어질 수 없다. 따라서 구내망의 구내통신선로설비는 구내의 인프라 구축에 매우 중요한 시설물이다. 이를 위해 국내에서는 초고속정보통신의 활성화를 위하여 1999년부터 초고속정보통신건물인증제도를 시행하고 있으며, 2004년1월1일부터는 공동주택의 특등급을 신설하여 세대내 광케이블이 시설되도록 요구하고 있다. 또한 국내의 구내통신선로설비에 대한 표준화는 한국통신기술협회에서 추진하고 있으며 현재까지 25개의 표준이 개발되었다. 주거용 건축물에 대한 표준을 2003년 12월에 개정하였으며 현재는 업무용 건축물에 대한 표준화 개정 연구를 진행하고 있다. 미국의 경우는 TIA를 통하여 자국내의 표준화 연구를 활발히 하고 있으며 이에 대한 내용을 근거로 국제표준화 연구를 진행하는 ISO에 제안하고 있다. 본 논문에서는 구내통신에 대하여 국제표준화와 미국을 중심으로 최근 표준화 동향에 대하여 조사 분석하고 이를 바탕으로 국내에서 제정하려고 하는 기술표준에 기여하고, 초고속정보통신건물인증제도와 국내 기술기준을 비교 분석을 통한 기술기준 개정방향을 기술하고자 한다.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.518-521
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• 2008

When constructing a high-speed railroad, the reduction of the distance between track centers and the width of track bed will save the construction cost. However the shortening the distance between track centers may cause the stability problems due to higher wind pressure. Therefore the extensive technical review and aerodynamical study should be performed to determine the adequate distance between track centers. In this study, the impact that the increase in wind pressure due to the change of aerodynamic phenomena with the change of the distance between track centers may have on two trains passing by each other was predicted, and the stability of train operation was analyzed in order to review the distance between track centers suitable to Honam HSR trains. And we estimated the aerodynamical effects by the results of the real train experiments by using KTX.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2822-2824
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• 2000

이 논문에서는 공장에서의 생산관리 및 구내 배전선로의 부하상태 관리용으로 개발한 다목적 실시간 원격 계측시스템을 제안하고 있다. 개발된 실시간 원격 계측시스템을 필요한 정보를 수집하는 원격단말장치와 수집된 정보를 제어 및 RS485 통신을 이용하여 정보를 전송하고 사용자 중심으로 그래픽 관리하는 호스트로 구성되어 있다. 특히, 기 설치된 생산설비에 대한 원격 생산관리 기능을 보유한 시스템을 확장하여, 이를 구내 배전선로에서 각 구간/선로별 전압, 전류, 누설전류 등의 정보 검출한다. 각 구간/선로별 전력, 전압, 전류 등 부하 운영상태 및 누설전류 등의 고장원인을 검출함으로써 전기화재 및 감전사고를 예방할 수 있는 감시 시스템을 제안하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.608-616
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• 2009

This paper presents a broadband CPS-fed Yagi-Uda antenna. The antenna has a feedline structure much simpler than other Yagi-Uda antennas and it provides more design flexibility in arranging the reflector. To improve the impedance matching, a tapered CPS line is inserted between the thick and thin feedlines. The proposed antenna exhibits the bandwidth of $3.9{\sim}5.9$ GHz (|G| < -10 dB) and the gain of $6.5{\sim}8$ dBi within that bandwidth. At the center frequency of 4.9 GHz, the antenna shows the gain of 7.4 dBi, and HPBW of $98^{\circ}$ along the x-z plane and $73^{\circ}$ along the x-y plane.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.5
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• pp.23-31
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• 2001

A very compact narrowband high-temperature superconducting microstrip filter using multiple coupled line resonators is designed and fabricated to effectively use the limited space of the wafer. The fabricated 12 pole filter has a center frequency of 1.79 GHz and a 3dB bandwidth of 7.63 MHz(0.43% fractional bandwidth). The filter also shows sharp skirt characteristics of 71 dB/MHz and 41dB/MHz blow and above the passband, respectively, and has an insertion loss of less than 0.5dB and a return loss of more than 15dB in the passband.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.12 s.115
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• pp.1150-1155
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• 2006

In this paper, the equivalent circuit of tapped-line that is applied in the band-pass filter is suggested and the value of an equivalent circuit is mathematically defined. An equivalent circuit of tapped-line is composed by open stub and transmission line that has negative electrical length, and the position of tapped-line and the value of resonator's length can be obtained by the impedance of resonator and the inverter. The new design method using equivalent circuit leads to very good agreement compared with theoretical value. The hair-pin band-pass filter using equivalent circuit of tapped-line shows the insertion loss of 1.1 dB and the return loss of 20 dB at the center frequency of 2 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1145-1150
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• 2012

In this paper, an improved Schiffman phase shifter is proposed using slot-coupled lines. It consists of the typical coupled lines and a simple rectangular slot which is placed in the ground plane underneath the coupled lines. Phase responses of the slot-coupled Schiffman phase shifter are analyzed in consideration of the phase velocity of two independent transmission modes and the characteristic impedance of slot-coupled line. The $905^{\circ}$ Schiffman phase shifters with high impedance ratio is realized at 2.4 GHz, which cannot be implemented with the conventional coupled lines. The measured results show that the bandwidth is around 74.2 % within the phase errors ${\pm}5^{\circ}$. The measured return loss is found to be better than 15.0 dB and insertion loss is less than 1.5 dB over the operating frequency band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.5 s.120
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• pp.547-552
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• 2007

In this paper, the coupled microstrip lines of hairpin type are applied to design a compact microstrip ring hybrid. When the gap decreases, three attenuation poles are created by coupling between the lines. The proposed structure can achieve a significant reduction of size and suppression of the harmonics. And it has the same frequency responses of conventional ring hybrid at 2.55 GHz. The harmonics are suppressed to below -20 dB up to 12 GHz, including the third harmonic. The ring part size of the proposed ring hybrid is reduced to one forth of the conventional ring hybrid. The measured frequency responses agree well with simulated ones.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.7
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• pp.768-773
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• 2012

A branch-line hybrid using microstrip artificial transmission lines(ATLs) with slotted-triangular patches is proposed. The proposed artificial transmission line is compact in structure as well as easy to adjust the characteristic impedance and electrical length of equivalent transmission line by changing the slot's parameters; hence, it is useful for miniaturizing conventional transmission lines. The designed branch-line hybrid, because of the use of the right angled isosceles triangular shaped artificial transmission lines as building blocks, has no useless empty space, and hence optimally miniaturized. A fabricated 3 dB branch-line hybrid shows the coupling variation of ${\pm}0.5$ dB and the phase difference between two output ports of $91^{\circ}{\pm}4^{\circ}$ within 15 % bandwidth at 2.45 GHz center frequency. The size of proposed branch-line hybrid is only 38% of the conventional branch-line hybrid.