• Title/Summary/Keyword: Pilot Detection

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Upstream Channel Structure for Bidirectional LMDS using CDMA (CDMA를 이용한 양방향 LMDS 역방향 채널구조)

  • Lim, Hyung-Rae;Park, Sol;Cho, Byung-Lok
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.2
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    • pp.408-414
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    • 1999
  • In this paper, we propose the method using coherent detection with time division multiple pilot signal for each users I reverse CDMA channel as the structure of reverse CDMA channel to apply CDMA to upstream channel of bidirectional LMDS. By using coherent detection with pilot signal in reverse CDMA channel, capacity can be improved when compared with noncoherent detection, but it is required to allocate pilot signal for all user. And then interference is increased due to allocate continuously the pilot signals. In this case channel capacity is decreased. The method f pilot allocation is needed that reduce this interference and keep synchronization effect using coherent detection, In the reverse link, the pilot allocated to each users at different time and not overlapped is possible solution for it. this pilot is proposed and analyzed its performance and capacity. The result is that proposed method has more increased capacity compared wit others.

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A Pilot Study to Deploy the Railway Conflict Detection and Resolution System in Korean Railway (열차경합 검지 및 해소시스템의 한국철도 적용에 관한 선행연구)

  • 오석문;홍순흠;최인찬
    • Journal of the Korean Society for Railway
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    • v.7 no.2
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    • pp.71-76
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    • 2004
  • In this paper, we propose a pilot study to deploy the Railway Conflict Detection and Resolution System(RCDRS) in the context of Korean Railway(KORAIL). KORAIL plans to deploy in near future RCDRS, which is a decision support module placed on the top level of the Railway Traffic Management System(RTMS). This study entails the review of the state-of-art researches and projects in the field of the railway traffic management, as well as the analysis of the traffic characteristics of the major railroad lines in KORAIL. The analysis provides a basis to choose a solution approach for the railway conflict detection and resolution problem that each individual line faces. This study plays a role as a pilot study for a full systematic approach, in which interactions between lines require further advanced analysis to take the entire KORAIL lines into consideration rather than a myopic approach.

Failure Detection Filter for the Sensor and Actuator Failure in the Auto-Pilot System (Auto-Pilot 시스템의 센서 및 actuator 고장진단을 위한 Failure Detection Filter)

  • Sang-Hyun Suh
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.4
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    • pp.8-16
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    • 1993
  • Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dim in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.

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Feasibility Study on the Landfill Monitoring and Leakage Detection System

  • Park, Jun-Boum;Kwon, Ki-Bum;Oh, Myoung-Hak;Mishra, Anil Kumar
    • Proceedings of the Korean Geotechical Society Conference
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    • 2007.09a
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    • pp.558-569
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    • 2007
  • It is important to obtain real-time data from long-term monitoring of landfills and develop leachate leakage detection system for the integrated management of landfills. A novel real time monitoring system and early leakage detection system was suggested in this study. The suggested monitoring system is composed of two parts; (1) a set of moisture sensors which monitor the areas surrounding the landfill, and (2) a set of moisture and temperature sensors which monitor the landfill inside. For the assessment for landfills stabilization, real-time monitoring system was evaluated in dry and wet cell of pilot-site. In addition, the grid-net electrical conductivity measurement system was also suggested as early leakage detection system. In this study, the field applicability of suggested systems was evaluated through pilot-scale field tests. The results of pilot-scale field model tests indicate that the grid-net electrical conductivity measurement method can be applicable to the detection of landfill leachate at the initial stage of intrusion, and thus has a potential for monitoring leachate leakage at waste landfills.

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Analysis of the Difference in Pilot Error by Using the Signal Detection Theory (신호탐지론을 활용한 조종사 Error 차이 분석)

  • Kwon, Oh-Young
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.18 no.1
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    • pp.51-57
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    • 2010
  • This study was to analyze the difference in pilot error by using the Signal Detection Theory. The task was to detect the targeted aircraft(signal) which is different shape from many other aircraft(noise). From the two experiments, we differentiated the task difficulty followed by change in noise stimuli. Experiment 1 was to search the signal stimuli(fighter plane) while the noise stimuli(cargo plane) were increasing. The results from the Experiment 1 showed the tendency to decrease the hit rate by increasing the number of noise stimuli. However, the false alarm rate was not increased. The sensitivity(d') showed quite high. In Experiment 2, a disturbance stimulus(helicopter) was added to noise stimuli. The result was generally similar to those of Experiment 1. However, the hit rate was lower than that of Experiment 1.

Frequency Domain DTV Pilot Detection Based on the Bussgang Theorem for Cognitive Radio

  • Hwang, Sung Sue;Park, Dong Chan;Kim, Suk Chan
    • ETRI Journal
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    • v.35 no.4
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    • pp.644-654
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    • 2013
  • In this paper, a signal detection scheme for cognitive radio (CR) based on the Bussgang theorem is proposed. The proposed scheme calculates the statistical difference between Gaussian noise and the primary user signal by applying the Bussgang theorem to the received signal. Therefore, the proposed scheme overcomes the noise uncertainty and gives scalable complexity according to the zero-memory nonlinear function for a mobile device. We also present the theoretical analysis on the detection threshold and the detection performance in the additive white Gaussian noise channel. The proposed detection scheme is evaluated by computer simulations based on the IEEE 802.22 standard for the wireless regional area network. Our results show that the proposed scheme is robust to the noise uncertainty and works well in a very low signal-to-noise ratio.

A New CDMA Uplink Channel Structure and DBCE Detection Scheme Using Staggered Burst Pilot (CDMA Uplink 채널 구조와 Staggered Burst 파일럿을 이용한 DBCE 검출기법)

  • 나종래
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.9A
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    • pp.1359-1367
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    • 2000
  • A new coherent detection scheme with data based channel estimation (DBCE) for CDMA/BP(staggered burst pilot in parallel) channel structure is proposed. Because the pilot burst initiates DBCE operation periodically it is shown to be remarkably stable to Gaussian noise and Doppler shift with proper parameter settings. In our own system parameter setting, there is a negligible loss(0.068 dB) in $E_{b}/N_{o}$ by the introduction of the burst pilot. When compared with an ideal coherent detection, the required $E_{b}/N_{o}$ on Doppler shift corresponding to the speed of 160Km/H is degraded less that 2.0 dB. the burst pilot can be implemented without complexity even though some extra correlators are needed for DBCE. This improvement is superior to the previously coherent CDMA detectors with external or internal pilot.

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Ship Detection for KOMPSAT and RADARSAT/SAR Images: Field Experiments

  • Yang Chan-Su;Kang Chang-Gu
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.144-147
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    • 2004
  • Two different sensors (here, KOMPSAT and RADARSAT) are considered for ship detection, and are used to delineate the detection performance for their data. The experiments are set for coastal regions of Mokpo Port and Ulsan Port and field experiments on board pilot boat are conducted to collect in situ ship validation information such as ship type and length. This paper introduce mainly the experiment result of ship detection by both RADARSAT SAR imagery and landbased RADAR data, operated by the local Authority of South Korea, so called vessel traffic system (VTS) radar. Fine imagery of Ulsan Port was acquired on June 19, 2004 and in-situ data such as wind speed and direction, taking pictures of ships and natural features were obtained aboard a pilot ship. North winds, with a maximum speed of 3.1 m/s were recorded. Ship's position, size and shape and natural features of breakwaters, oil pipeline and alongside ship were compared using SAR and VTS. It is shown that KOMPSAT/EOC has a good performance in the detection of a moving ship at a speed of 7 kts or more an hour that ship and its wake can be imaged. The detection capability of RADARSAT doesn't matter how fast ship is running and depends on a ship itself, e.g. its material, length and type. Our results indicate that SAR can be applicable to automated ship detection for a VTS and SAR combination service.

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ATSC Digital Television Signal Detection with Spectral Correlation Density

  • Yoo, Do-Sik;Lim, Jongtae;Kang, Min-Hong
    • Journal of Communications and Networks
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    • v.16 no.6
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    • pp.600-612
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    • 2014
  • In this paper, we consider the problem of spectrum sensing for advanced television systems committee (ATSC) digital television (DTV) signal detection. To exploit the cyclostationarity of the ATSC DTV signals, we employ spectral correlation density (SCD) as the decision statistic and propose an optimal detection algorithm. The major difficulty is in obtaining the probability distribution functions of the SCD. To overcome the difficulty, we probabilistically model the pilot frequency location and employ Gaussian approximation for the SCD distribution. Then, we obtain a practically implementable detection algorithm that outperforms the industry leading systems by 2-3 dB. We also propose various techniques that greatly reduce the system complexity with performance degradation by only a few tenths of decibels. Finally, we show how robust the system is to the estimation errors of the noise power spectral density level and the probability distribution of the pilot frequency location.

Back Tracing Calculation Method for the Leakage Detection in Water Distribution System (상수관망에서 누수탐지를 위한 역추적계산법)

  • Kwon, Hyuk Jae
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.5
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    • pp.611-619
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    • 2013
  • In this study, Back Tracing Calculation Method was developed to determine the leakage location and leakage amount. Previously developed determination method of monitoring location and newly developed Back Tracing Calculation Method were applied to the sample pipe network and real size pilot plant. After leakage was assumed in the pilot plant, leakage location and leakage amount could be traced by Back Tracing Calculation Method. From the results, it was found that Back Tracing Calculation Method can be applied for the leakage detection in water distribution system. Furthermore, this method can be applied for the pressure management or leakage detection as a pressure control method in water distribution system.