• Title, Summary, Keyword: 차.지상 간 통신장치

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The Optimization of Data Transmission between CBTC On-board Equipment and Ground System (CBTC 시스템에서의 차상-지상간 정보전송 최적화에 대한 검토)

  • Choi, Kyu-Hyoung;Yoon, Yong-Ki
    • Proceedings of the KIEE Conference
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    • pp.231-232
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    • 2004
  • 궤도회로를 사용하지 않고 무선통신을 이용하여 지상-차상간 정보를 송수신하고 열차속도를 제어하는 CBTC 시스템에서, 지상장치와 차상장치간의 열차속도 검지 및 열차제어에 필요한 정보교환을 최적화하기 위한 방안에 대하여 검토하였다. 국가연구개발사업으로 추진중인 경량전철 신호제어시스템 개발에 적용하여, 시스템 최적화를 통한 시스템 설계에 적용하였다.

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A Study on Software Static Analysis Method on IEC 62279 (IEC 62279 규격의 소프트웨어 정적분석에 관한 연구)

  • Jin, Zhe-Huan;Li, Chang-Long;Lee, Jae-Ho;Kim, Jae-Sik;Lee, Key-Seo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.10 no.4
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    • pp.513-519
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    • 2015
  • Static analysis is one of the software source code analysis tools. 9 static analysis methods of three groups are recommended by international electro-technical commission about software safety related standard in IEC 62279. In this paper we choose the proper static analysis method from IEC 62279 about the train wayside communication system, Shorten the time of railway signalling software development using LDRA tools. And it wil be useful to improve the effective development of the safety-related software.

An Investigation on the Interface between CBTC On-board Equipment and Other Train-born Systems (CBTC 화상장치와 차량시스템간의 인터페이스에 대한 검토)

  • Choi, Kyu-Hyoung;Yoon, Yong-Ki
    • Proceedings of the KIEE Conference
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    • pp.227-228
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    • 2004
  • 궤도회로를 사용하지 않고 무선통신을 이용하여 지상-차상간 정보를 송수신하고 열차속도를 제어하는 CBTC 시스템에서, CBTC 차상장치와 추진제어장치와 제동제어장치, 출입문 개폐장치 등의 차량내 각종 차량제어장치들간의 인터페이스를 죄 적화하기 위한 방안에 대하여 검토하였다. 또한 현재 국가연구개발사업으로 추진중인 경량전철 신호제어시스템 개발에 적용하여, 시스템 최적화를 통한 시스템 설계 및 시험평가에 적용하였다.

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Train interval control and train-centric distributed interlocking algorithm for autonomous train driving control system (열차자율주행제어시스템을 위한 간격제어와 차상중심 분산형 연동 알고리즘)

  • Oh, Sehchan;Kim, Kyunghee;Choi, Hyeonyeong
    • 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.

Cooperative Transmission Scheme for Mobile Satellite Broadcasting Systems (이동 위성 방송 시스템을 위한 협력적 전송 기법 연구)

  • Ahn, Do-Seob;Park, Dong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.9
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    • pp.890-899
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    • 2009
  • One of major services for the next generation mobile satellite system will be multimedia broadcasting and multi-casting service(MBMS). An integrated satellite and terrestrial network can be considered to provide those services seamlessly and cooperatively. This paper presents efficient cooperative transmission architectures for integrated satellite and terrestrial network. First, an integrated satellite and terrestrial system architectures is introduced, and several cooperative transmission architectures for the integrated system are derived. Extensive performance simulation results reveal that the proposed architectures can improve the system performance and make an efficient transmission.

A Study on Frequency Sharing of Fixed Satellite Service with Microwave Landing System (고정위성업무와 마이크로파착륙장치 간의 주파수 공유 연구)

  • Jun, Byung-Kyu;Kang, Ji-Han;Lim, Sang-Seok;Lee, Jae-Wook;Oh, Dae-Sub;Gam, Hye-Mi
    • Journal of Advanced Navigation Technology
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    • v.15 no.1
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    • pp.11-17
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    • 2011
  • In this paper, we consider the frequency sharing feasibility of Fixed Satellite Service (FSS) with Microwave Landing System (MLS) allocated in the C-band. On the basis of characteristics of MLS and FSS suggested by ITU and safety standards of MLS by ICAO, three interference scenarios are built and numerical simulations are carried out for investigating the frequency sharing between the two systems. From the simulation results, we calculate the separation distance between MLS and FSS ground antennas, required for frequency sharing by employing standard protection limits regulating the interference to noise ratio (I/N) of the receiver.

Structural Analysis of Spaceborne Two-axis Gimbal-type Antenna of Compact Advanced Satellite (차세대 중형위성용 2축 짐벌식 안테나의 구조해석)

  • Park, Yeon-Hyeok;You, Chang-Mok;Kang, Eun-Su;Oh, Hyun-Ung
    • Journal of Aerospace System Engineering
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    • v.12 no.2
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    • pp.37-45
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    • 2018
  • A two-axis gimbal-type antenna for a Compact Advanced Satellite (CAS) is used to efficiently transmit high resolution image data to a ground station. In this study, we designed the structure of a two-axis gimbal-type antenna while applying a launch lock device to secure its structural safety under a launch environment. To validate the effectiveness of the structural design, a structural analysis of the antenna was performed. First, a modal analysis was performed to investigate the dynamic responses of the antenna with and without the mechanical constraints of the launch lock device. In addition, a quasi-static analysis was performed to confirm the structural safety of the antenna structure and bolt I/Fs between the antenna base and the satellite. The suitable range of constraint force on the launch lock device was also determined to ensure the structural safety and mechanical gapping of the ball & socket interfaces, which places multi-constraints on the azimuth and elevation stage of the antenna.

A Study on Apparatus of Smart Wearable for Mine Detection (스마트 웨어러블 지뢰탐지 장치 연구)

  • Kim, Chi-Wook;Koo, Kyong-Wan;Cha, Jae-Sang
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.2
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    • pp.263-267
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    • 2015
  • current mine detector can't division the section if it is conducted and it needs too much labor force and time. in addition to, if the user don't move the head of sensor in regular speed or move it too fast, it is hard to detect a mine exactly. according to this, to improve the problem using one direction ultrasonic wave sensing signal, that is made up of human body antenna part, main micro processor unit part, smart glasses part, body equipped LCD monitor part, wireless data transmit part, belt type power supply part, black box type camera, Security Communication headset. the user can equip this at head, body, arm, waist and leg in removable type. so it is able to detect the powder in a 360-degree on(under) the ground whether it is metal or nonmetal and it can express the 2D or 3D film about distance, form and material of the mine. so the battle combats can avoid the mine and move fast. also, through the portable battery and twin self power supply system of the power supply part, combat troops can fight without extra recharge and we can monitoring the battle situation of distant place at the command center server on real-time. and then, it makes able to sharing the information of battle among battle combats one on one. as a result, the purpose of this study is researching a smart wearable mine detector which can establish a smart battle system as if the commander is in the site of the battle.

Optimal Sampling Method of Censored Data for Optimizing Preventive Maintenance (예방정비 최적화를 위한 중도절단 자료의 최적 샘플링 방안)

  • Lee, In-Hyun;Oh, Sea-Hwa;Li, Chang-Long;Yang, Dong-In;Lee, Key-Seo
    • Journal of the Korean Society for Railway
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    • v.16 no.3
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    • pp.196-201
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    • 2013
  • As there is no failure data for the entire lifecycle of a product, when analyzing reliability measures based on early failure data only, there may be a significant error between the estimated mean life and the real one, because it can be underestimated, or on the other hand, it can be overestimated when analyzing reliability measures based on a large amount of censored data with the failure data. To resolve the issue, this study proposes an optimal sampling estimation procedure that selects the proportion of censored data to estimate the optimal distribution with the idea that the estimated distribution could be approximated as closely as the real life distribution. This would work if we sampled the optimal proportion on the censored data, because failure data has real intrinsic distribution in any situation. We validate the proposed procedure using an actual example. If the proposed method is applied to the maintenance policy of TWC (Train to Wayside Communication) system, then we can establish the optimal maintenance policy. Thus, we expect that it will be effective for improvement of reliability and cost savings.

DESIGN AND FABRICATION OF S-BAND DIPLEXER FOR LEO TT&C APPLICATION (저궤도 위성 관제용 S-대역 다이플렉서 설계 및 제작)

  • Ahn, Sang-Il;Park, Dong-Chul
    • Journal of Astronomy and Space Sciences
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    • v.24 no.4
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    • pp.397-408
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    • 2007
  • Diplexer is one of core devices needed to communicate with satellite using single ground antenna by separating uplink and downlink signal. This paper presents the design of the S-band diplexer for LEO TT&C application, especially for KOMPSAT (KOrea Multi-Purpose SATellite). To cope with requirements such as high handling power, low insertion loss, air-cavity resonator with high quality factor was considered as one of design drivers. Design was started with predicting unloaded Q and equivalent circuit from the structure of air-cavity resonator. For the convenience of adjustment, the coupling factor placed between resonators was estimated from COTSEM (Electro-Magnetic) simulator, EESOF $ADS^{TM}$, and expressed with 2-order polynomial regression. To improve the isolation between transmitting part (Tx) and receiving part (Rx), the inductive and capacitive attenuation poles were inserted between $4^{th}\;and\;6^{th}$ resonator respectively. The fabricated diplexer consists of two bandpass filters and each filter has eight resonants. From the measurement, it was shown that major requirements such as 0.5dB of insertion loss, 20dB of return loss and 100dB of isolation were fully satisfied within passband.