• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.277-282
• /
• 1999

Recently , the use of steel fibers has been increased in flexural members and beams of concrete structures ; such as bridge decks, highway roads, runway of airport , buildings , ete.. An experimental investigation of the shear behavior of high-strength reinforced concrete beams using input steel fiber was conducted. However only a few experimental tests have been carried out under static loading . The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking , crack patters, fracture modes. The load versus strain and load versus deflection relation were obtained from the static test.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.20 no.2
• /
• pp.39-46
• /
• 2012

Mountain Aerodromes are aerodromes with special characteristics, provided in mountains for the needs of air transport operations. Mountain Aerodromes are approved for restricted use and are reserved for pilots and aircrafts special requirement. In this study, we surveyed the operating system and the characteristics of the Mountain Aerodromes in the ski stations of the French Alps mountainous region. We introduced the necessity and the relevant regulations for Mountain Aerodromes in Korea.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.10a
• /
• pp.424-429
• /
• 2013

The trolley carrying the pod moves along by the airfield runway. The pod through the trolley are subjected to vibration arising from the ground state, the precision optical components in the pod can have a significant impact. The road tests were conducted by using the measurement pod to remove the risk for the project. The measurement pod was composed with the ACRA, sensors, battery. The accelerometers were attached to get the acceleration through the road condition. The PSD envelop was calculated by FFT from the acceleration. The driving safety was proven through comparing the measurement data and MIL-STD-810G specification.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.7
• /
• pp.557-564
• /
• 2021

This paper describes an automatic landing approach algorithm for fixed-wing UAVs using waypoint guidance. The proposed algorithm utilizes simple 2D Dubin's vehicle pre-simulations in planning the waypoints for landing approach. The remaining time to reach the runway is also estimated in the pre-simulation, and it is used for altitude control. The performance of the designed algorithm was verified by simulations and flight tests.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.162.3-162
• /
• 2001

The essence of ABS(Anti-skid Brake System) control is to continuously adjust brake pressure to maintain optimum brake torque. This optimum level should balance tire and runway friction its peak value, yielding maximum braking deceleration. It influences not only the deceleration and the taxing distance of an aircraft, but also the strength and the fatigue life of the landing gear. In this paper, an ABS control algorithm is developed with a dynamics model of 5-DOFD(Degree of Freedom). The algorithm is verified by simulations and the simulation results are presented. The dynamics model is simulated by the computer.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.9 no.1
• /
• pp.21-25
• /
• 2009

The results of a recent case study for material characterizations and structural evaluation to design asphalt overlay thickness of William P Hobby airport in Houston, Texas are presented herein. The existing runway 12R-30L of Hobby airport consisted of thick asphalt overlay over Portland Cement Concrete (PCC) and the localized surface shoving as evident in the closure of surface groove has been observed recently. Using the field cored asphalt concrete mixtures, measurements of percent air voids, asphalt content and aggregate gradation were conducted to find out the causations of surface shoving and groove closure. The FAA layered elastic program, LEDFAA was utilized to evaluate pavement structural conditions for new asphalt overlay. Two different composition assumptions for existing pavement were made to evaluate the pavement as followings: 1) APC, Asphalt Concrete Overlay over PCC pavement and 2) AC, Asphalt Concrete pavement. Based on laboratory testing results, a ratio of percent passing #200 to asphalt content ranged 1.1 to 2.2, which is considered a high ratio and a tendency of tender mix design was observed. Thus, the localized surface shoving and groove closure of the runway 12R-30L could be attributed to the use of excessive fine contents and tender mix design. Based on the structural evaluation results, it was ascertained that the analysis assuming the pavement structure as AC pavement gives more realistic structural life when the asphalt overlay is thicker enough compared to PCC layer because the existing PCC pavement under asphalt overlay acts more like a high quality base material.

• Journal of Advanced Navigation Technology
• /
• v.28 no.3
• /
• pp.254-261
• /
• 2024

Accurate guidance during landing and take-off is important, and instrument landing system (ILS) has been used for stability and verification. Regular inspections are conducted for stable operation, and there is research to perform inspection using drones in addition to ground vehicles and measurement aircraft. Using SDR and single board computer, which can receive wide frequency range, we designed a small system that receives and processes localizer signals through GNU Radio. To check signal processing characteristics through GNU Radio, we simulated with MATLAB Simulink and confirmed the theoretical values. Difference in depth of modulation (DDM) and approach angle can be calculated when the aircraft enters the runway. And GNU Radio implemented real-time signal processing wirelessly using transmission control protocol (TCP). This gives the results within the error of 0.5% when the aircraft entered the runway center line and 0.27% for the angle of 1° degree. Compared to the inspecting and maintaining ILS signals using aircraft or ground vehicles, it is possible to implement a receiving system using small SDR that can be mounted for drone.

• Aerospace Engineering and Technology
• /
• v.13 no.1
• /
• pp.1-9
• /
• 2014

Goheung aeronautical center is located in the area of Goheung of which land is reclaimed from sea and has a runway of length 700m, width 25m with test facility which has been used for flight test of UAV and small aircraft. To support the enhancement of aircraft safety, 1090ES ADS-B ground system as the ground surveillance system has been implemented. ADS-B system based on GPS and digital data link provides the function of enhancing the aircraft safety through flight information among aircrafts. This paper gives the result that the implementation of ADS-B ground system and the flight test with onboard ADS-B transmitter has been conducted.

• Journal of Positioning, Navigation, and Timing
• /
• v.2 no.2
• /
• pp.115-121
• /
• 2013

For the auto-landing operation of an air vehicle, the possibility of auto-landing operation should be first evaluated by testing the navigation performance through a flight test. In general, navigation performance is tested by analyzing north/east/down (NED) errors relative to reference equipment whose precision is about 8~10 times higher than that of a navigation system. However, to evaluate the auto-landing operation of an air vehicle, whether the air vehicle approaches a glide path aligned with the runway, within a specific error, needs to be examined rather than examining the north/east errors of the navigation system. Therefore, the longitudinal/lateral errors of air vehicle heading need to be analyzed. In this study, a method for analyzing the longitudinal/lateral errors of a navigation system was proposed as the navigation performance test method for evaluating the safety during the auto-landing of an air vehicle. Also, flight tests were performed six times, and the safety of auto-landing was examined by analyzing the performance using the proposed method.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.519-524
• /
• 2003

In this report, a longitudinal adaptive flight control law is presented for the automatic landing system of a Japanese automatic landing flight experiment vehicle (ALFLEX). The longitudinal adaptive flight control law is designed to track an output of the vehicle to a guidance signal from the guidance portion of the automatic landing system. The proposed adaptive control law in the attitude control portion adjusts the controller gains continuously online as flight conditions change, in spite of the existence of unmodeled dynamics. The number of the controller gains to be adjusted is decreased to 1/2 from the previous studies. Computer simulation involving six-degree-of-freedom (DOF) nonlinear flight dynamics is performed to examine the effectiveness of the proposed adaptive control law. In order to verify the influence of the dispersion of the initial conditions, the Monte Carlo simulation is also applied. The initial conditions are more widely dispersed than the previous studies. As a result, except under the unsuitable initial conditions, the ALFLEX successfully landed on the runway.