• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.7
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• pp.557-564
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• 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
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• 2001.10a
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• pp.162.3-162
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• 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
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• v.9 no.1
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• pp.21-25
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• 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.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.1-9
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• 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
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• v.2 no.2
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• pp.115-121
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• 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
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• 2003.10a
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• pp.519-524
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• 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.

• The Research Journal of the Costume Culture
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• v.24 no.3
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• pp.349-357
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• 2016

As a solemn and serious uniform, military uniform can be differentiated easily from any other clothing in the aspects of color, material and style. Inspired by military uniform, fashion designers have been applying military uniform elements into modern fashion design in recent years, which helps to bring military uniform from the trench onto international fashion runway. The primary method of this research is theory analysis method and exampling study method. Based on the collected materials of modern military uniform, this paper takes the fashion and cultural study theory of the famous American scholar Susan B. Kaiser as the leading theory to analyze four subject positions embodied in military uniform, including nation, rank, gender and time and space. By analyzing the subject positions embodied in military uniform, it shows the rich cultural connotation of military uniform and the function of various small details. Meanwhile, by giving specific examples, this paper explores the influences of military uniform on modern fashion design in respect to color, style, material, pattern and accessory. Through the conduct of this research, it comes to the conclusion that military uniform also has the characteristics and properties described in the fashion and cultural theory of Susan B. Kaiser, in addition, designers can be inspired by every specific object around them, which shows the talents of designers.

• The Research Journal of the Costume Culture
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• v.28 no.4
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• pp.562-571
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• 2020

Intermedia refers to the convergence of media. The advance of intermedia has not only facilitated the delivery of brand messages in contemporary fashion shows but also facilitated interactive communication. This study investigated the mediating roles played by various media in fashion and fashion shows, focusing on the phenomenon of intermedia in contemporary fashion shows. To investigate the impact of intermedia on contemporary fashion shows, we conducted a social network analysis-a promising approach for research into fashion trends. Analyzing 159 fashion-related articles published in the 2000s, we extracted intermedia-related words (n=253). The relation-ships between keywords made an analysis of between centrality, and cluster variables applied Clauset-Newman-Moore by using KrKwic and NodeXL programs. The results of the between centrality analysis indicated that the most important factors in contemporary fashion shows are "models" and "stages." We found that the impacts of intermedia on contemporary fashion shows can be divided into four categories: "model performance," "symbolic stage management," "new media utilization," and "convergence in arts." Our analysis thus identified considerable synergy between the characteristics of intermedia and contemporary fashion shows. These results have found intermedia-related commonalities in intermedia and fashion show, and this might increase customer interest in fashion, a positive outcome for the fashion industry.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.353-356
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• 2007

Asphalt pavements of the airport in service were monitored to construct new runway and taxiway and longitudinal cracks were found on the pavements. The sources of the longitudinal cracks were the low density which was caused by the longitudinal cold joint with asphalt Pavement constructions and the excessive loads of aircraft. Therefore, the echelon paving method using a 12m-wide screed finisher was used to eliminate longitudinal cracks. When the echelon paving is used, construction of the longitudinal joint is changed so that the compaction of the unconfined edge of the first lane is delayed until the second lane is placed. In conclusion, the use of this construction method results in the density of the longitudinal joint being equal to that of the adjacent mat.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.45-54
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• 2007

In this study, the function of TIS-B(Traffic Information Service-Broadcasting), Runway incursion prevention, conflict warning, way-point assignment were evaluated using ground-to-ground surveillance test bed of KARI which was based on ADS-B(Automatic Dependant Surveillance-Broadcasting) concept. VDL(VHF Data Link) based on STDMA protocol was used as a data link, and an UAT(Universal Access Transceiver) was included to get the TIS-B information, and four ground vehicles and two aircraft were included as rover units. The main purpose of this test bed was to realize the ADS-B concept for the application of ground surveillance and to evaluate its performance.