• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.545-555
• /
• 2011

Presently, The Regular Block System(Automatic, Interlocking block system) is usually used during the operation of block section. However, In case that the regular block system fails because of the failure of the fixed signals and block equipment or in case of the unexpected emergency which should drive on the single line due to the accidents in the double line section or the repair work of the single line, the Substitute Block System to use the driving permission license(mapping ticket and paper) is used. In case of the operation of the opposite line and the temporary one line, the safety gets worse and the SBS may cause the fatal accidents such as a head-on & a rear-end collision. Also, the unmanned railroad stations has recently increased owing to the effective operation of the stations, for it is difficult to execute the SBS in their absence. As a result, the increase of the operation time made the train delayed. Being on the rise of these problems, in this study, we analyzed the problems and difficulties of the SBS on one line which is lacking stability and safety and on the sections combined between maned and unmaned railroad stations. And we proposed the suitable method in KORAIL referring to the examples of European & Japan railways lately. According to the passing of the high tech time, If the new SBS equipped with stability and safety is executed, it will contribute to the effective operation of trains and the satisfaction of KORAIL customers in the future.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.25 no.4
• /
• pp.398-404
• /
• 2015

In this paper, we describe the design and performance of a prototype multi-rotor unmaned aerial vehicle( UAV) platform featuring an inertial measurement unit(IMU) based autonomous-flying for use in bluetooth communication environments. Although there has been a fair amount of study of free-flying UAV with multi-rotors, the more recent trend has been to outfit hexarotor helicopter with gimbal to support various services. This paper introduces the hardware and software systems toward very compact and autonomous hexarotors, where they can perform search, rescue, and surveillance missions without external assistance systems like ground station computers, high-performance remote control devices or vision system. The proposed system comprises the construction of the test hexarotor platform, the implementation of an IMU, mathematical modeling and simulation in the helicopter. Furthermore, the hexarotor helicopter with implemented IMU is connected with a micro controller unit(MCU)(ARM-cortex) board. The micro-controller is able to command the rotational speed of the rotors and to get the measurements of the IMU as input signals. The control simulation and experiment on the real system are implemented in the test platform, evaluated and compared against each other.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.3D
• /
• pp.259-267
• /
• 2012

The development of construction automation systems is proposed as a potent solution to the difficulties encountered by the construction industry and the preparation for the rapidly changing construction environment. A research concerning an intelligent excavation system has taken place since 2006. The intelligent excavation system has several functions for environment sensing, 3D site modeling, work planning, work path generation, unmaned control, and information management. This paper presents a space information model and a work path simulator for work planning and work path generation which is one of key technologies required to apply the earthwork system to the real world. A data structure for an earthwork site is suggested. It overcomes the limitations of previous data structures such as Quadtree and Octree. The work path simulator can generate an effective work path with considering information on work environment, equipment and operator's heuristic. The work path generated by the simulator is compared with that suggested by human operators.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.4
• /
• pp.551-558
• /
• 2016

We analyzed wind speed over South Korea for HALE UAV(High Altitude Long Endurance Unmaned Aerial Vehicle) flight safety. Annual variation of wind speed at 200 hPa showed that winter season was stronger than summer. According to latitude, wind speeds in January and August were found to be $52{\sim}74m\;s^{-1}$ and $15{\sim}26m\;s^{-1}$, respectively. Wind speed was stronger(weaker) at lower latitudes than higher latitudes in winter(summer). Frequency(%) of wind speed less than threshold value($18m\;s^{-1}$) for the operation date was investigated. The days showing the frequency greater than 60 % in all altitudes of surface ~ 50 hPa showed the range of 1 ~ 33 days at 7 stations. Operation date was the longest period at Gosan. The appropriate date of HALE UAV operation at Gosan and Osan is considered as the middle of July ~ middle of August and end of July ~ early August, respectively. These results can be used to determine the operation date of HALE UAV.

• Journal of Advanced Navigation Technology
• /
• v.20 no.3
• /
• pp.232-237
• /
• 2016

As a possible standardization of wireless local area network (WLAN), IEEE 802.11 LRLP is under discussion in order to support long range and low power (LRLP) communication for internet of things (IoT) including drones and many other IoT devices. In this paper, an efficient adaptive resource unit allocation scheme for uplink multiuser transmission in IEEE 802.11 LRLP networks is proposed. In the proposed scheme, which adopts OFDMA random access based transmission scheme of IEEE 802.11ax, in order to enhance the efficiency of the slotted OFDMA random access, access point (AP) traces the history of the sizes of successfully transmitted uplink data, and adjusts the sizes of resource units for the next uplink multiuser transmission adaptively. Our simulation results corroborate that the proposed scheme significantly improves the system throughput.

• Journal of Navigation and Port Research
• /
• v.29 no.6 s.102
• /
• pp.567-572
• /
• 2005

Trade between nations has been globalized since establishing the WTO(World Trade Organization). By lowering trading barriers under the WTO's system, trade in goods has been gradually increased It requires global logistic system that transports goods in between nations. To save cost of product, cargo of product is containerized and container ships to carry container cargo is going to be bigger: In the market, there are many vendors to provide artificial intelligent modules to operate container terminal. In order to integrate automated container terminal system easily and successfully, this thesis proposes high-level XML/ JMS( eXtensive Markup Language/Java Message Service) communication model and multi-agent based system architecture to share knowledges, solve problems, and active objectives by cooperating between autonomous and intelligent agents that are developed by 3rd party companies in the market. This thesis analyzed current situation of advanced automated container terminal with case studies on implemented systems and difficulties to develop automated container terminal system, reviewed technologies of intelligent agent, communication and automation that unmaned automated container terminal is required.

• Convergence Security Journal
• /
• v.19 no.4
• /
• pp.97-105
• /
• 2019

With the possibility of wireless control of the aircraft by Nicola Tesla, Unmanned Aerial Vehicle(UAV) was mainly used for military and defense purposes with the rapid development through World War I and II. As civilian applications of unmanned aerial vehicles have expanded, they have been used with various services, and attempts have been made to control various environmental changes and risk factors of unmanned aerial vehicles. However, GPS spoofing, Jamming attack and security accidents are occurring due to the communication in the unmaned aerial vehicle system or the security vulnerability of the unmanned aerial vehicle itself. In order to secure introduction of Unmanned aerial vehicle, South Korea has established Unmanned Aerial Vehicle verification system called Airworthiness Certification. However, the existing cerfication system is more focused on test flight, design and structure's safety and reliability. In this paper, we propose a unmanned aerial vehicle system model and propose security functional requirements on unmanned aerial vehicle system in the corresponding system model for secure-introduction of Unmanned Aerial Vehicle. We suggest the development direction of verification technology. From this proposal, future development directions of evaluation and verification technology of Unmanned Aerial Vehicle will be presented.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.4
• /
• pp.591-598
• /
• 2017

The changes of technology and the size of markets for unmaned aerial vehicle are getting bigger presently. Damage happens because of user's poor operation since accesses to the drones are easy. To minimize the damage, drone's stabilized flight skills are required, and controlling the motor to balanced speed is also needed. Thus, the essay shows that we use Arduino as a main control device for controlling a drone, and used acceleration sensor and gyro sensor for the drone stabilization. Also, we made it able to hover at a certain height by using a sonar sensor. We also controlled a drone by using an Android application, and made the drone hover stably at 0~2 meters.

• Journal of the Korean Solar Energy Society
• /
• v.34 no.4
• /
• pp.17-22
• /
• 2014

The design of a fuel cells stack is important to get optimal output power. This study focuses on the evaluation of fuel cell system for unmaned aerial vehicles (UAVs). Low temperature proton exchange membrane (LTPEM) fuel cells are the most promising energy source for the robot applications because of their unique advantages such as high energy density, cold startup, and quick response during operation. In this paper, a 600 W open cathode LTPEM fuel cell was tested to evaluate the performance and to determine optimal operating conditions. The open cathode design reduces the overall size of the system to meet the requirement for robotic application. The cruise power requirement of 600 W was supported entirely by the fuel cell while the additional power requirements during takeoff was extended using a battery. A peak of power of 900 W is possible for 10 mins with a lithium polymer (LiPo) battery. The system was evaluated under various load cycles as well as start-stop cycles. The system response from no load to full load meets the robot platform requirement. The total weigh of the stack was 2 kg, while the overall system, including the fuel processing system and battery, was 4 kg.

• Journal of Advanced Navigation Technology
• /
• v.15 no.2
• /
• pp.181-188
• /
• 2011

A small UAVs(Unmaned Aerial Vehicles) have limited by the payload capacity which requires miniaturization of a navigation system. In this paper, the performance of the lightweight and small sized AHRS(Attitude Heading Reference System), which is self-developed, is evaluated at low acceleration environment. The designed AHRS adopts the commercial low-cost MEMS sensors. A quaternion-based attitude calculation method, which eliminates singularity with relatively simple algebra, is used. In an attitude correction algorithm, the Kalman filter is used with accelerometers and magnetometers combined. The fabricated AHRS is also evaluated with reference to a COTS(Commercial Off-The-Shelf) AHRS which reports a number of successful applications to a small UAVs. The test results show that the measurements from the fabricated AHRS provide proper attitude output data with acceptable amount of differences(horizontal axis 0.5$^{\circ}$, vertical axis 1.5$^{\circ}$) in test environment.