• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.4
• /
• pp.91-97
• /
• 2005

As the developing of industry, the nonlinear equipments as inverter, converter, SMPS(Switching Mode Power Supply) and motor have been increased. But the sensitive electronic loads to the power quality, such as computers and other electronic equipments, have been spreaded out very fast. Thus, the power quality(PQ) problems and the real time power quality monitering(PQM) are one of the important issues in industry and building area for the intelligent control of the systems. One of them, PQM using PLC(Power Line Communication) have good merits that can send and receive the PQ information without any new network line. This paper presents the PQM hardware and software to monitor the PQ information by using PLC that meets the categories of IEEE Std. 1159.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.295-297
• /
• 2005

본 논문에서는 지금까지 각각 독립적으로 운전되었던 동북아시아(대한민국, 북한, 러시아) 전력시스템이 계통 연계를 통하여 얻을 수 있는 경제적 효과에 대한 평가 프로그램의 개발에 대하여 설명한다. 본 평가 프로그램의 목적는 향후 동북아 전력시스템의 계통 연계시 각 나라들의 발전소 건설 및 운용, 그리고 연계설비(Tie line)의 투자비용을 최소화할 수 있는 방안을 찾아 내는 것이다. 이를 통해 독립적으로 운전되는 것에 비해 계통연계를 통한 것이 보다 높은 경제적인 효과를 거둘 수 있음을 최종적으로 보이고자 한다. 문제를 좀 더 쉽고 빠르며 효과적으로 풀기 위하여 신규 발전설비와 연계선로에 대한 계획측면의 변수와 발전양와 선로에 흐르는 조류양의 제약 그리고 각 노드에서의 전력수급 조건 둥의 운전측면의 변수를 함께 포함시킨 선형 계획법 (LP, Linear Programming) 모델 로 정식화한 뒤 최적화 프로그램인 CPLEX를 통하여 해를 구한다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.5
• /
• pp.845-853
• /
• 2009

This study recognize the problems about the High-speed IT building certification system and the technical standards of telecommunication facility, broadcasting public receiving facility including Home-network facility which are installed at apartments for the successful building of the Ubiquitous city that the government is driving and suggested a sweeping change of the housing law interrelated for making up a housing efficiency grade-display system and systematizing the maintenance by solutions. Also, presented the integrate-construction model designs separately of the residential IT line about the buildings applied to technical standards, the building acquired second grade below of High-speed IT building and the building when the above solutions get to he systematized.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.42 no.4
• /
• pp.53-62
• /
• 2005

In this paper, we implement a 40kbps narrowband powerline communication modem which is able to high transfer rate than conventional powerline communication technology by using the chirp technique that is one of the spread spectrum techniques. A modem that implement in this paper used the CEBus standard and a symbol that the linear variable frequency signal of 100$\sim$380kHz is kept for 25us. Experimental results, we verified the possibility that communication technology with the Chirp technique can make transfer rate more than 40kbps at narrowband communication.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.3
• /
• pp.379-387
• /
• 2000

In this paper, to transmit and receive the differently polarized wideband signals simultaneously with a single antenna system, the wideband, dual-frequency and dual-polarized(WDFDP) microstrip array antenna is proposed and designed. This antenna operates simultaneously at 14.25 GHz and 12.50 GHz. To extend to two dimensional array, microstrip feed line and coaxial probe through via-hole are used. The experimental results show that the proposed WDFDP microstrip antenna can be used in the compact portable terminals with a single antenna system and the characteristic of the resonators in this antenna produces a greatly enhanced bandwidth.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.5
• /
• pp.1076-1081
• /
• 2007

In this paper, we propose a new switch structure for time division duplex(TDD) system. The existing TDD structure utilizes a circulator fur isolation characteristic between ports. However, the circulator produces intermodulation distortion signals which are undesired signal because of its nonlinear properties. The proposed circuit is composed of a modified branch-line hybrid coupler which controls the signal flow while the isolated port is open-/short- terminated. In order to prove the validity of the presented structure, the switch circuit is fabricated and measured at 2.3GHz, the center frequency of Wibro service system.

• Korean Journal of Optics and Photonics
• /
• v.14 no.6
• /
• pp.583-587
• /
• 2003

In this paper, the optimal performance of optical second-order polarization mode dispersion (PMD) compensation has been investigated theoretically in terms of minimization of the root-mean-square (RMS) pulse broadening. The optimal compensation vector in feedforward-type second-order PMD compensation has been derived, and the RMS pulse broadening factor after the optimal second-order PMD compensation has been analytically calculated. The calculated result has been compared with the previously reported simulation result where numerically optimized feedback scheme was adopted. They are in good agreement, which verifies the validity of the derivation. The investigation in this work will form the basis for the implementation of the feed-forward-type second-order PMD compensation.

• 한국방재학회:학술대회논문집
• /
• 2011.02a
• /
• pp.38-38
• /
• 2011

일반적으로 레일마모는 열차의 주행안전 및 승차감에 미치는 영향이 크고, 소음 진동의 주요원인으로 작용한다. 또한 레일마모가 발생할 경우 궤도구조의 파괴를 촉진시킴으로써 차량 및 궤도유지보수비를 크게 증가시킨다. 따라서 구간 특성 및 환경 영향 인자 등 현장에서 발생하는 마모 원인을 체계적으로 분석함으로써 마모를 저감할 수 있도록 차량운행 조건과 선로선형 및 궤도구조를 설계하는 것은 중요한 과제이다. CART(Classification And Regression Tree; 분류와 회귀나무) 분석은 패키지화된 좋은 분류 및 예측도구 기법으로 나무의 상위 분리수준에서 일반적으로 나타나는 가장 중요한 입력변수들을 사용하는 등의 입력변수를 선정하는 경우 매우 유용하다. 본 연구에서는 다변수 구간특성 및 환경인자를 고려한 검측 자료 상관관계 분석을 위한 회귀 나무기반 모델(TBM: Tree Based Model) 분석 수행을 위해 지하철 2호선 마모 데이터와 마모 데이터에 영향을 미치는 각종 다변수 구간특성 및 환경인자를 사용하였다. 2호선 지하철의 구간특성 인자 및 환경인자는 레일의 종류, 레일의 위치, 도상, 곡률반경, 캔트 슬랙 및 운행 일수 등으로 구분하였다. 레일의 종류는 ks-50kg과 ks-60kg 두 종류의 레일이 있으며, 레일의 위치는 지상과 지하로 크게 구분할 수 있다. 도상은 콘크리트 도상, 자갈 도상과 일부 구간의 방진상 콘크리트 도상으로 구분할 수 있으며, 곡률반경은 직선구간과 완화곡선 구간 및 최소 250m부터 627m까지 분포된 원 곡선 구간으로 구분할 수 있다. 캔트 간격은 최소 96cm 부터 120cm 간격으로 구분하며, 슬랙은 5~9cm에 분포하고, 운행 기간은 해당 기간 동안 유지보수 이력이 없는 구간을 선정하여 2005년부터 2006년까지 4번에 걸쳐 검측된 지하철 2호선 내선 마모데이터를 사용하였다. 총 X1부터 X7까지 총 7개의 구간특성 또는 환경특성을 영향인자로 선정하였으며, 이러한 영향인자에 의해 결정되는 종속 인자로 Y1인 직마모와 Y2인 측마모를 선정하여 이 중 실질적으로 지하철 궤도의 성능 평가에 주요 판단인자로 사용되는 측마모와 구간특성 및 환경영향인자와의 상관관계 분석을 수행하였다. 해당 마모 데이터가 검측되는 기간 동안 유지보수 이력이 없는 12272 point의 데이터를 검출하였고 CART 프로그램을 이용하여 데이터를 분석하였으며, CART 프로그램의 해석을 위해 종속변수인 직마모량은 각 검측 지점의 마모량에 해당하는 등급으로 변환하여 분석을 수행하였다. 레일의 마모에 영향을 미치는 구간특성 및 환경인자와 종속 변수로 사용된 레일의 마모량 사이의 CART를 이용한 상관관계 분석은 실제 구조물에서 영향인자간의 상관 관계와 유사하며, 추후 연구에서는 이를 바탕으로 하여 정량화된 검측 데이터를 종속변수로 하여 구간특성 또는 환경인자 등 외부 영향인자를 고려한 궤도 검측데이터와의 상관관계 분석을 수행할 계획이다.

• Journal of the Korean Society for Railway
• /
• v.14 no.5
• /
• pp.433-441
• /
• 2011

It is a fact that the straightening of track alignment is one of the undoubted ways to improve the train speed on conventional lines, while that requires huge investment resources. Therefore, the operation of a tilting train as well as the minimum improvement of track is suggested as an effective and economical alternative way for the speed-up of conventional lines. Since a driving mechanism of tilting train is different from those of existing trains, in order to make sure its operation safety and stability on conventional line, the performance of track and roadbed must be preferentially evaluated on the conventional line. Furthermore, it is necessary to estimate the tilting-train-induced roadbed response in detail since the roadbed settlement can lead to the track deformation and even derailment. In this research, the patterns of wheel load and lateral force were monitored and analyzed through the field tests, and the derailment coefficient and degree of wheel off-loading were calculated in order to evaluate the tilting train running safety depending on the running speeds (120km~180km) on the conventional line. Moreover, roadbed pressure, settlement and acceleration were also observed as tilting-train-induced roadbed responses in order to estimate the roadbed stability depending on the running speeds. Consequently, the measured derailment coefficient and degree of wheel off-loading were satisfied with their own required limits, and all of the roadbed responses were less than those of existing high-speed train (KTX) over an entire running speed range considered in this study. As a result of this study, the tilting train which will be operated in combination with existing trains is expected to give no adverse impact on the conventional line even with its improved running speed.

• Journal of IKEEE
• /
• v.3 no.1 s.4
• /
• pp.79-85
• /
• 1999

In this paper, the resistive mixer for 5.86Hz wireless LAN, main part receiving system, was designed and implemented. The noise characteristics and the linearity in the base band was superior. For the use of local oscillator of mixer, dielectric resonator of stable output and temperature characteristics was designed. For the electrical tuning by the capacitance variation of varactor diode, the microstrip line and magnetic coupling characteristics of the dielectric resonance was used. It was obtained that gain of the proposed resistive mixer containing the RF cable loss, is -13.8dB, the conversion loss of frequency converter is -12 dB, and the output power of local oscillator is 1.67 dBm.