• Journal of the Korean Society for Railway
• /
• v.14 no.6
• /
• pp.507-514
• /
• 2011

Recently, we developed a new subway train with many cooperative companies. The main controller of the subway train is Control and Monitoring System (TCMS), so we conducted requirement analysis of TCMS considering system performance, easy maintenance and service oriented flexibility. Hence, we adopted new bus architecture and QNX as a Real-time Operating System (RTOS) and developed hardware systems. The functions of TCMS are employed into two computers, service computer and control/monitor computer, to increase on their performance and to yield easy maintenance and to satisfy customer needs. The TCMS controls and monitors control devices equipped in the train through various protocols which are implemented in hardware. In order to evaluate the performance of the system and to satisfy reliability, various experiments including EMC/ECI were performed. Now the TCMS is installed on the newly developed train and is under performance evaluation through test driving.

• Journal of the Korea Society for Simulation
• /
• v.15 no.2
• /
• pp.23-29
• /
• 2006

This paper studies the Internet stream server which serves multimedia stream services such as VoD and MoD. The Internet multimedia stream server is developed to provide 50 users with continuous multimedia stream contents simultaneously. This paper focuses on introducing design concepts, operation details and on evaluating system performance and doing sensitivity analysis with respect to the change of the system components. The performance evaluation is performed using simulation in order to identify the system component that mostly affects the system performance. The sensitivity analysis shows the service delay rates of the multimedia stream server depending on the user's service request pattern. Also, the analysis is made on the utilization rates of the core system components such as the PCI bus and the Ethernet card, and on the system performance change by adding more system components.

• The KIPS Transactions:PartC
• /
• v.13C no.7 s.110
• /
• pp.881-888
• /
• 2006

The position of the bridged tap is determined by that of the outlet in most modern apartments, since most of the indoor wiring utilizes the bus wiring structure when deploying the indoor communication line. These bridged taps deteriorate transmission performance in the specific frequency at the time of high-speed multimedia communication, which uses a high frequency bandwidth, since the duality of return loss worsens and line attenuation increases rapidly. As a result, analysis on this phenomenon is required. In this study, the test model is created by modeling the intercommunication facility of the apartment that is the most representative residential house type, and by understanding the structure and the environment of the indoor wiring. Also, how the bridge tap affects performance is analyzed when the VDSL service is provided, so that problems of intercommunication lines can be identified and methods for improving the proper intercommunication line can be suggested, which is suitable for accommodating high-speed multimedia service of the future.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.745-752
• /
• 2011

Light Rail Vehicle(LRT) is "New Transit System" that has transportation capacity as well as physical size of vehicle is in-between bus and subway. The demand of LRT system is increasing rapidly; both domestically and internationally. Reason being is that it is more economical and eco-friendly compare to existing heavy rail vehicle. Especially, Busan Subway Line 4 K-AGT (Rubber-tired LRT) being the first of its kind to start revenue service in Korea, it is very much likely that application of its demand will continue to increase. Considering its trend, study to reduce implementation cost of LRT is being pursued in many different aspects; reducing construction cost is one that aspect. In this study, on-site application of 'Up-Down Turnout System' implementation research has been carried out which can replace existing 'Left-Right Turnout System'. When safety of its type gets verified, application of this system to line which intends to use K-AGT, Shin-Lim Line and Dong-Book Line, expects to save its construction cost. This thesis paper reports ongoing research of AGT 'Up-Down Turnout System' development and main component design factors, fundamental principle, performance test result.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.2
• /
• pp.600-619
• /
• 2015

We propose a cost-efficient hybrid algorithm for online location updates that efficiently combines feature point detection with the online trajectory-based sampling algorithm. Our algorithm is designed to minimize the average trajectory error with the minimal number of sample points. The algorithm is composed of 3 steps. First, we choose corner points from the map as sample points because they will most likely cause fewer trajectory errors. By employing the online trajectory sampling algorithm as the second step, our algorithm detects several missing and important sample points to prevent unwanted trajectory errors. The final step improves cost efficiency by eliminating redundant sample points on straight paths. We evaluate the proposed algorithm with real GPS trajectory data for various bus routes and compare our algorithm with the existing one. Simulation results show that our algorithm decreases the average trajectory error 28% compared to the existing one. In terms of cost efficiency, simulation results show that our algorithm is 29% more cost efficient than the existing one with real GPS trajectory data.

• Journal of Preventive Medicine and Public Health
• /
• v.23 no.3 s.31
• /
• pp.316-323
• /
• 1990

To analyze of determinants influencing the utilization of the rural health sub-centers (HSCs), 116 of 144 HSCs in Kyong Gi Do, were selected for this study. The self-administered questionnaire covering the environment and the characteristics of doctors working in the HSCs was sent to HSCs by mail. 105 questionnaires were returned of which 88 were completed and use in the study. The dependant variable was the total number of medical care visits to the HSCs from January 1, 1990 to March 31, 1990. Data was analyzed by multiple regression analysis. The results were as follows : First, the more time required to set from the HSCs to nearest hospital or clinic, the higher the utilization of the HSCs. Second, the more geographically accessible the HSCs was, the more utilization the HSCs. Third, the older of the HSCs doctors were, the more utilization of the HSCs. Fourth, the higher frequency of bus service from the HSCs to town, the more utilization of the HSCs. Fifth, the more time required from the HSCs to town, the more utilization of the HSCs. Therefore, the determinants influencing the utilization of the rural HSCs in Kyong-Gi Do, are mostly geographical accessibility of medical care.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.5 no.3 s.11
• /
• pp.1-12
• /
• 2006

Nowdays ITS is being installed in each local autonomous entity, and BIS installation and operation is prior to other ITS sub systems for the public service. The methods of positioning md wireless communication in BIS are DSRC+DSRC, GPS+wireless communication, Beacon+Beacon, which are chosen and operated as the local features. Before this study, the before and after survey of BIS' quality have only been done without performance evaluation of BIS. So the method of BIS' evaluation have been established including performance test in this paper. And the evaluation of some BIS' reliability and efficiency have been done using the reliability of arriving data and the wireless communication response rates after choosing typical BIS' sub system.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.64 no.4
• /
• pp.212-219
• /
• 2015

Korea's first tram (so called "tram"), which was commenced the operation on May 4, 1899 of late Joseon Dynasty and run until 1968, played a pivotal role of public transportation. However, tram as new transportation mean is being recognized as traffic congestion problem becomes issue due to geometric automobile increase and reckless urban plan after stoppage of tram service. Tram has an advantage of inexpensive construction cost and eco-friendly means compared to existing and city railway, carrying more passengers rather than existing bus, excellent connectivity of existing transportation because of easy accessible to destination in the city center. Therefore, tram, what is called "Green Rvolution of Public Transportation", has a dreaming of revival and in the process of pushing. We suggest the accident type which might break out in the early stage of tram introduction and preventive measures by surveying the accident cases of tram advanced country, and study the crossing control measures.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.5
• /
• pp.611-616
• /
• 2018

In the cost based pool market in Korea, there is no compensation of reactive power because the fuel cost for reactive power is relatively low compared to that of active power. However, the change of energy paradigm in the future, such as widespread integration of distributed renewable energy source, will prevent the system operator from mandating the reactive power supply without any compensation. Thus, in this study, we propose the reference voltage of the 345 kV transmission system that minimizes the reactive power supply. This is closely related to the economic dispatch of reactive power aiming at minimizing the compensation cost for the reactive power service. In order to verify the effectiveness of the proposed reference voltage, the simulations are performed using the IEEE 14 bus system and the KEPCO real networks. The simulation results show that a voltage lower than the current reference value is recommended to reduce the reactive power supply and also suggest that the current voltage specification for the 345 kV system needs to be reviewed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.3
• /
• pp.410-415
• /
• 2002

This paper describes the implementation of a SoC(System-on-a-Chip) and an ISDN communication terminal by the SoC in ISDN network. The SoC has been developed with the functions of 32-bit ARM7TDMI RISC core processor, network connection with S/T interface, TDM--bus interface and voice codec, user interface. And we also review the developed software structure and the ISDN service protocol procedures which are working on the SoC. And finally this paper describers a structure of an ISDN terminal equipment using the implemented SoC and terminal software.