• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.60-66
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• 2011

The$PM_{10}$ concentrations in the underground should be monitored for the health of commuters on the subway system. Seoul Metro and Seoul Metropolitan Rapid Transit Corporation are measuring several air pollutants regularly. In this paper, the reliability of the instruments using light scattering method is improved with the help of a linear regression analysis technique to measure the $PM_{10}$ concentrations continuously in the subway stations. In addition, an USN monitoring system is implemented to display and record the data of $PM_{10}$, CO/$CO_2$, humidity, and temperature. To transmit and receive these measured sensor data, 2.4GHz Zigbee, 424MHz wireless communication, and CDMA M2M method are applied and evaluated.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1309-1316
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• 2018

Cattle estrus detection system based on Internet of Things is designed and implemented by using Arduino pro-mini, gyroscope, acceleration sensor, bluetooth master and slave module. The implemented system measures cattle's moving and the measured data are transmitted to the computer connected to RX module by bluetooth TX module. They are plotted in 2-dimensional graph on the computer monitor and the number of transition at each sensor axis are calculated from the graph. The detected and gathered data from the system are analyzed by the proposed algorithm to decide which cows are in the estrus or not. The method to apply bluetooth scatternet is shown and the proposed system can be used to increase the success rate of artificial insemination in normal estrus by detecting the cow's behaviors such as the number of jumping. In this paper, the implemented cattle behavior detecting the system(TX module) are strapped on cattle's leg and it measures the cattle behaviors for determining where that a cattle is estrus or not by the proposed algorithm.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.82-85
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• 2002

This paper proposes a new position detection method for train speed control using the PDOA(Phase Difference of Arrival). This method aims to apply to AGT(Automated Guide way Transit) systems, operated with driverless. So it is absolutely required to range, calculate and decide a train position precisely. This system consists of VRS (Vehicle Radio Set) and WRS(Wayside Radio Set). The VRS transmits a wireless signal to the WRS, the controller calculate a straight line with the PDOA. Next step calculate an exact position using track DB. This paper includes the concept, configuration, analysis and results of this method.

• Korean Security Journal
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• no.44
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• pp.169-198
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• 2015

The purpose of present study is to provide an efficient 'Disaster Emergency Communication System' (below DECS) to deal with serious disaster situations in national levels. Currently, DECSs such as the VHF, UHF, and TRS are worked to control some disaster situations in the world. However, new system such as for sending the correct image and big data is more likely to need than current the DECSs in the comtemporary societies. Several serious disaster events such as the Sam-Poong Department Store Collapse, Daegu Subway Fire, and Sewol Submerge event, nevertheless, there was not the DECS based on the field in South Korea. In July 2014, finally, South Korean government started to provide a PS-LTE system which is the new and one system with fire fighting, police, army, railway. however, there are no many academic studies for DECSs to deal with disaster situations in South Korea. The present research highlights to explore an efficient DECS of Korean styles to fix some national security and public safety. The paper provides three key findings: first is how to make a unified Korean DECS based on PS-LTE. Second is how to make sure the frequency of 700MHz levels to communicate in the shady areas. Three is what kinds of communication facility is adequate for fixing PS-LTE DECS.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.294-301
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• 2013

The particle matter concentrations in the subway stations should be monitored and controlled for the health of commuters on the subway system. Seoul Metro and Seoul Metropolitan Rapid Transit Corporation are measuring several air pollutants regularly. In this paper, the reliability of the cheap instruments using light scattering method is improved with the help of a linear regression analysis technique to measure the $PM_{10}$ concentrations continuously in the subway stations. In addition, a monitoring system is implemented to display and record the data of $PM_{10}$, $CO_2$, humidity, and temperature. To transmit and receive these measured sensor data, CDMA M2M wireless communication method is applied.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.5
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• pp.152-161
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• 2017

The CBTC(Communication based Train Control) system employed on 2.4GHz ISM band adopt the IEEE802.11.x standard. Therefor communication time delay, distortion and data losses will be produced. To overcome these problems, CPSK(Continuous Phase shift keying) modulated DS/SS(Direct Sequence Spread Spectrum) transmitter with 908MHz carrier frequency is proposed. Through the eye diagram and scatter diagram the performance is analysed. And the phase noise characteristic of the local oscillator is measured about 60dBc/Hz, this means that the phase noise performance is very good compared to the signal. Reference frequency suppression of the 2nd local oscillator is 50dB below compared to the signal. Through the polarities of the complementary signal equally probable, the line spectrum of the output spectrum is eliminated. The nonlinear effects which introduce the spectral spreading or spectral regeneration is reduced remarkably.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.68-78
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• 2016

Safety is the most important factor for train control systems. Model-based design and safety activities for way-side equipment in train control systems are important factors. Model-based architecture verification was carried out to develop an effective control system, which is represented by model-based failure mode and effects analysis (FMEA). An architecture verification method was created based on FMEA to take advantage of a design model and improve the train safety control system. Case studies were applied to architecture verification scenarios, and the results demonstrate the usability of the method. The improved method is expected to reduce the cost and time in the conceptual design for future development of model-based verification train control systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.543-550
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• 2018

The rapid growth of IoT technology induced by the fourth industrial revolution has resulted in research into various types of wireless sensors, and applications based on this technology are prevalent in many areas. However, among the various sites where this technology is used, railway bridges and tunnels with lengths of tens of kilometers have problems with data acquisition, due to the signal noise induced by the long distance measurement and EMI induced by the high voltage power feeding system, when conventional electric sensors are used. To overcome these problems, many studies on fiber optic sensors have been conducted as a substitute for the conventional electric sensors. However, restrictions on the types of fiber optic sensors have limited their application in railways. For this reason, a hybrid measurement system with IoT based wireless data communication, in which both electric and fiber optic sensors can be applied simultaneously, has been developed. In this study, in order to evaluate the applicability of the hybrid measurement system developed in the previous study, a real-time test for 4 types of measurement environments, which reflect possible railway sites, is performed. As a result, it was confirmed that the signals from both the electric and fiber optic sensors, which were acquired at a remote area in real-time, showed good agreement with each other and that this measurement system has the potential to handle sensors with a sampling rate of 2.5 kHz. In the future, it is expected that the IoT-based hybrid measurement system will contribute to the improvement of structural safety by enabling real-time structural health monitoring when applied to various measurement sites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.573-584
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• 2016

The train control system is a facility to ensure model-based design and safe train operation, and its safety is the most important factor for system introduction, complexity of the design information and traceability etc. Therefore, the model-based design and safety activities regarding the way-side equipment of a train control system is also highlighted. To solve this problem, In this paper, model-based design was carried out first to develop an effective train control system, which is represented by SysML(System Modeling Language). The test scenarios that can take advantage of the design model were created to improve the train safety control system. Case studies of a model-based design of a train-centric train control system were applied to the test scenarios; the results demonstrated its usability. The improved activity over the test highlighted the safety improvement approach, and it is expected to reduce the cost and time in the conceptual design of a future development model-based train control system.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.802-810
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• 2006

For a thorough train control, the precise train position detection is necessarily required. The widely used current way for train position detection is the one of using track circuits. The track circuit has a simple structure, and has a high level of reliability. However trains can be detected only on track circuits, which have to be installed on all ground sections, and much amount of cost for its installation and maintenance is needed. In addition, for the track circuit, only discontinuous position detection is possible because of the features of the closed circuit loop configuration. As the recent advances in telecommunication technologies and high-tech vehicle-based control equipments, for the train position detection, the method to detect positions directly from on trains is being studied. Vehicle-based position detection method is to estimate train positions, speed, timing data continuously, and to use them as the control information. In this paper, the features of GPS navigation and DR navigation are analyzed, and the navigation filters are designed by constructing vehicle-based train position detection method by combining GPS navigation and DR navigation for their complementary cooperation, and by using kalman filter. The position estimation performance of the proposed method is also confirmed by simulations.