• Journal of the Korean Society for Railway
• /
• v.17 no.2
• /
• pp.148-155
• /
• 2014

This practical study investigates the effects of job satisfaction as a result of the stresses felt by many dispatchers who work in the subway industry in the Seoul metropolitan area. Factors that cause stress are assessed. The organization system, inappropriate compensation, workplace culture, and job requirements, among several types of organizational stresses are significantly related to job satisfaction. The results of the analysis indicate that there is a close link between job satisfaction and dispatcher communication factors. This paper suggests stress-relief measures for dispatchers who must handle a variety of civil complaints and improper communications with field departments based on the analysis of the answers to descriptive questionnaire items.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.1060-1066
• /
• 2008

Bi-modal tram is a new conceptual transit mean for public transportation integrating thoroughfare and railroad vehicle's characteristics together. This paper describes about a software design which will be applied to an automatic driving system, which is called NCS (Navigation Control System), considering such multiplicity of mechanical characteristic. The NCS adopts propulsion, braking, and direction control functions for a tram and utilizes various sensors to fully take control over such functions. In this paper, we defined and analyzed the capabilities of the NCS. Those capabilities are designed with a UML 2.0 based object-oriented modeling technique. Moreover, to ensure the complete operation of such capabilities, a communication protocol (which is capable of controlling sensors, propulsion, brakes, and traveling directions) is designed here. Throughout the paper, firstly, all the NCS related functions are discussed in accordance with the equipments they are belonged to; secondly the UML modeling application techniques for the defined functions and protocols for the communications between equipments are introduced; and lastly a validation process for the design specifications is going to be discussed.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.51 no.8
• /
• pp.371-378
• /
• 2002

This paper presents the rapid and accurate algorithm for fault detection and location estimation in the transmission line. This algorithm uses wavelet transform for fault detection and harmonics elimination and utilizes least square error method for fault impedance estimation. Wavelet transform decomposes fault signals into high frequence component Dl and low frequence component A3. The former is used for fault phase detection and fault types classification and the latter is used for harmonics elimination. After fault detection, an adaptive data window technique using LSE estimates fault impedance. It can find a optimal data window length and estimate fault impedance rapidly, because it changes the length according to the fault disturbance. To prove the performance of the algorithm, the authors test relaying signals obtained from EMTP simulation. Test results show that the proposed algorithm estimates fault location within a half cycle after fault irrelevant to fault types and various fault conditions.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.6
• /
• pp.9-13
• /
• 2009

In the three axis control of Low Earth Orbit (LEO) satellite by using reaction wheel and gyro, a reaction wheel produces the control torque by the wheel speed or momentum, and a gyro carries out measuring of the attitude angle and the attitude angular velocity. In this paper, the dynamic modelling of LEO is consisted of the one from the rotational motion of the satellite with basic rigid body model and a flexible model, in addition to the reaction wheel model. A robust controller $(H_\infty)$ is designed to stabilize the rigid body and the flexible body of satellite, which can be perturbed due to disturbance, etc. The result obtained by $H_\infty$ controller is compared with that of the PI (Proportional and Integration) controller, which has been traditionally using for the stabilizing LEO satellite.

• International Journal of Advanced Culture Technology
• /
• v.10 no.4
• /
• pp.569-575
• /
• 2022

This is a research thesis on the development of a monitoring and diagnosis device that prevents the risk of an accident through monitoring and diagnosis of a modular Main Circuit Breaker (MCB) using Vacuum Interrupter (VI) for Korean high-speed rolling stock. In this paper, a comprehensive MCB monitoring and diagnosis was performed by converging vacuum level diagnosis of interrupter, operating coil monitoring of MCB and environmental temperature/humidity monitoring of modular box. In addition, to develop an algorithm that is expected to have a similar data processing before the actual field test of the MCB monitoring and diagnosis device in 2023, the cluster analysis and factor analysis were performed using the WEKA data mining technique on the big data of Korean railroad transformer, which was previously researched by Tae Hee Evolution with KORAIL.

• International journal of advanced smart convergence
• /
• v.12 no.1
• /
• pp.208-219
• /
• 2023

Recently, as mega-urbanization progresses, urban logistics centered on large cities is growing rapidly, and logistics transportation is increasing due to the lack of logistics infrastructure and the operation of a delivery system using cargo trucks in the city center. being cited as a cause. In order to solve this problem, domestic researchers are conducting research on the development of " Urban Underground railway Logistics System" that minimizes the initial infrastructure construction cost by utilizing the existing urban railway facilities in the city. Therefore, this paper analyzed the usage environment of the actual urban railway station to which the system will be applied in order to derive candidates for the test bed selection of "Urban Underground railway Logistics System". The evaluation criteria for test bed candidate role selection were established, and the candidate group derived from the Brown & Gibson model was used to evaluate the candidate group and derive the candidate role. A review of the results was conducted to contribute to the establishment of a test bed for the " Urban Underground railway Logistics System" under development.

• International journal of advanced smart convergence
• /
• v.12 no.1
• /
• pp.220-229
• /
• 2023

The development of logistics technology due to the 4th Industrial Revolution and logistics 4.0 has changed the logistics environment from offline to online, and the growth of the online market has accelerated due to the recent increase in non-face-to-face delivery due to COVID-19. Such growth in the online market has expanded the logistics market for delivery, and contributes to creating an advanced logistics ecosystem as last mile services and logistics technologies begin to grow together. As traffic and environmental problems arise as a result, interest in transportation means of cargo increases, and changes to cargo electric vehicles and delivery cycles are being considered. However, since mass transportation of transportation focused on terminal delivery such as cargo electric vehicles and delivery cycles is limited in handling large quantities in urban areas, methods for efficiently transporting cargo while considering the environment are being devised. In order to solve such environmental problems and increase the efficiency of logistics delivery in urban areas, technologies using underground spaces based on existing urban railroads are being developed. In this study, a study was conducted on the establishment of evaluation criteria for selecting a test bed, which is a space for applying the system.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.381-382
• /
• 2023

Frequent accidents occur when workers at construction sites leave the safety zone, and particularly in the past 5 years, 9 fatal accidents occurred at the Korea Railroad Corporation due to train accidents on other tracks during track work. With the Severe Accident Punishment Act taking effect in January 2022, it is a priority to secure a safe work environment for workers at industrial (construction) sites. Therefore, there is a need to manage workers' departure from the safety zone (construction zone) and to facilitate communication within the construction zone. In this study, a mobile edge computing CCTV system is proposed that uses geofencing to determine whether workers are working in the danger zone, which can judge and respond in real-time to the ever-changing field environment. The proposed system is mobile and flexible, rather than server-based fixed CCTV. However, since it is designed mainly based on images, it has limitations in recognition rate depending on the environment such as distance, viewing angle, and illumination. As a way to compensate for this, it is required to develop more reliable equipment by combining technologies such as LiDAR and Radar.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.7
• /
• pp.647-654
• /
• 2016

Indoor localization based on visible-light communication using the received signal strength intensity (RSSI) has been widely studied because of its high accuracy compared with other wireless localization methods. However, because the RSSI can vary according to the inclination and azimuth of the receiver, a large error can occur, even at the same position. In this paper, we propose a visible-light communication-based 3-D indoor positioning algorithm using the Gauss-Newton technique in order to reduce the errors caused by the change in the inclination of the receiver. The proposed system reduces the amount of computations by selecting the initial position of the receiver through the linear least-squares method (LSM), which is applied to the RSSIs, and improves the position accuracy by applying the Gauss-Newton technique to the 3-D nonlinear model that contains the RSSIs acquired by the changes in the azimuth and inclination of the receiver. In order to verify the validity of the proposed algorithm in an indoor space with dimensions of $6{\times}6{\times}3m$ where 16 LED lights are installed, we compare and analyze the errors of the conventional linear LSM-based trilateration technique and the proposed algorithm according to the changes in the inclination and azimuth of the receiver. The experimental results show that the location accuracy of the proposed algorithm is improved by 82.5% compared to the conventional LSM-based trilateration technique.

• Management & Information Systems Review
• /
• v.32 no.5
• /
• pp.119-134
• /
• 2013

The purpose of this study was to explore the labor relations and job attitudes on KORAIL's employees. The subject of the study was the members of the Gyeongbuk Headquarters of Korea Railroad Corporation(KORAIL). For the purpose of analysis, a survey was conducted for 155 members of KORAIL Gyeongbuk Headquarters, and 119 questionnaires were used for the final analysis. The results of the analysis are as follows: First, there are 3 powerful parties in the KORAIL system of labor relations as Union, Management and Goverment. The KORAIL system of labor relations is very unstable and rigid. The labor union of KORAIL engaged in a desperate struggle against the management. Second, there are significant differences in job satisfaction, communication, organizational commitment, job attitudes between union members and non-union members. These results indicate that establish a labor-management community culture, communication need to be more activated. The activation of communication can contribute to building confidence in labor-management relationship.