• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.436-443
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• 2019

The purpose of this paper is to establish a predictive model by analyzing the influence and correlation of factors affecting the fuel consumption of unmanned helicopters in Captive Flight Test. In this study, a four-factor two-level full factorial experiment was designed and tested using the design of experiments, results were analyzed to derive the main effects and interactions of the factors, and the predictive model was established through regression analysis. It is expected that the results from this study contribute to carrying out Captive Flight Test efficiently and the improvement of the test capability of Electronic Testing Range.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.40-47
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• 2019

This paper proposes the environment construction and test method of system integration laboratory (SIL) and system integration test (SIT) for verification of interface between onboard equipment and ground control equipment of unmanned aerial systems (UAS). This research also describes the interface environment between subsystems built in SIL and verification methods for the systems' operation logic through simulated flights. Similarly, the paper handles the ground integration test process of UAS in the real testing environments.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.511-517
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• 2015

Sound absorption capability of the flame resistant treated sawdust-mandarin peel composite particleboard was were estimated by two microphone transfer function methods. The weight of flame resistant treated board slightly increased by the treatment. The treatment improved fire retardant performance by decreasing the charred area of flame resistant treated board. Sound absorption capabilities of flame resistant treated sawdust-mandarin peel composite particleboard, in the entire estimated frequency range of 500-6,400 Hz was slightly lower than those of the control specimen. Sound absorption capability of both the control and flame resistant treated sawdust-mandarin peel composite particleboards were higher than that of commercial gypsum boards, being widely used as a sound absorber for ceiling at the estimated frequency.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.236-244
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• 2007

The 40% scaled vehicle of Smart UAV has been developed for the investigation of basic flight characteristics and the verification of flight control algorithm. The similar gimbal hub and drive train with the full scale UAV were implemented and a forced air cooling reciprocating engine was installed. The various kind of tests were conducted for the major components of the vehicle. The important performance and mechanical endurance of the fabricated vehicle were identified by ground and hovering test.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.397-399
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• 2002

가상교육이 활성화됨에 따라 많은 가상대학이 진행되고 있다. 이러한 가상대학운영에서 몇몇의 문제점이 제기되고 있는 것 중에서 학습자의 학습도를 평가하는 평가방법이 중요한 문제로 부각되고 있다. 이런 문제를 보완하고자 본 논문에서는 평가에서 나타날 수 있는 문제를 분석하고 오답 일치율, 신상정보 유사도, IP주소 유사도, 시험시간 유사도 등을 이용하여 담합 여부를 파악하고, 담합 행위를 방지하기 위하여 무작위 문항 제시에 의한 온라인 시험 방법으로 이를 개선하려는 시스템을 구현하였다. 그 결과 Threshold 간을 조절함으로 학습자의 담합 행위를 검출할 수 있었으며 무작위 문항 제시 방법에 적절한 시간 설정값을 조절함으로 기존 평가에서의 담합 행위를 80%정도 방지할 수 있었다.

• Journal of Advanced Navigation Technology
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• v.25 no.6
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• pp.510-516
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• 2021

Recently, the range of utilization and demand for unmanned aerial vehicle (UAV) has been continuously increasing, and research on the construction of a separate operating system for low-altitude UAV is underway through the development of a management system separate from manned aircraft. Since low-altitude UAVs also fly in the airspace, it is essential to establish technical standards and certification systems necessary for the operation of the aircraft, and research on this is also in progress. If the operating standards and certification requirements of the aircraft are presented, a test method to confirm this should also be presented. In particular, the accuracy of small UAV's navigation required during flight is required to be more precise than that of a manned aircraft or a large UAV. It was necessary to calculate a separate navigation error. In this study, we presented a test method for deriving navigation errors that can be applied to UAVs that have difficulty in acquiring long-term operational data, which is different from existing manned aircraft, and conducted verification tests.

• Asian Journal of Turfgrass Science
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• v.19 no.1
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• pp.27-38
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• 2005

This study was conducted to find out withering and dying trends of turfgrasses on the base of tree, and to investigated how much area of turfgrasses withering and dying were progressed on angle of inclination at golf course. Turfgrasses withering and dying on base of trees on slope was extended more to the down-solpe direction than to the up-solpe direction. This trend was common in all experiment plot. Turfgrasses on the base of trees were withered and dead by competing with tree root fur nutrients and moisture in soil. But the trend of the withering and dying in some experiment plots occurred by soil erosion following turfgrass withering and dying occurring on upside ridge. This trend was generally appeared in region of tree community at upside ridge. The form of turfgrass withering and dying on the base of tree in some experiment plots was similar to that of the tree crown. This withering and dying from occurred at the $11^{th}$ experiment plot in Ji San Golf Course and the $6^{th}$ experiment plot in East valley Golf Course.

• Fire Science and Engineering
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• v.26 no.1
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• pp.1-9
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• 2012

Since accommodation, public space and service areas where people stay for all day occupy about 70% of a huge cruise ship, they have to be protected from the fire. International Maritime Organization has resolved that a water mist system should be equipped in this cruise ship according to SOLAS II-2 Reg. 10.6 and FSS code Ch. 7. The water mist system consists of mist nozzles, pressure vessels, section valves and pump unit etc. In particular, the water mist nozzles should be recognized by fire tests in accordance with IMO Res. MSC 265(84). In this study, the fire tests for cabin, corridor, public space and storage area have been conducted to develop the water mist nozzles appropriate to the regulation. Totally 5 types of nozzles were developed and have satisfied the whole performance requirements.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.7
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• pp.611-619
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• 2016

This paper proposes a collision prevention system for an agricultural unmanned helicopter. The collision prevention system consists of an obstacle detection system, a mapping algorithm, and a collision avoidance algorithm. The obstacle detection system based on a LiDAR sensor is implemented in the unmanned helicopter and acquires distance information of obstacles in real-time. Then, an obstacle mapping is carried out by combining the distance to the obstacles with attitude/location data of the unmanned helicopter. In order to prevent a collision, alert is activated to an operator based on the map when the vehicle approaches to the obstacles. Moreover, the developed collision prevention system is verified through flight test simulating a flight pattern aerial spraying.

• Journal of Navigation and Port Research
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• v.33 no.1
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• pp.35-41
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• 2009

A waypoint tracking algorithm(WTA) is designed for Unmanned Surface Vehicle(USV) in which water-jet system is installed for propulsion To control the heading of USV for waypoint tracking, the steering nozzle of water-jet need, to be controlled. Firstly, target heading is calculated by using the position information of waypoints input from the land control center. Secondly, the command for the steering nozzle of water-jet is calculated in real time by using the heading and the rate-of-turn( ROT) from magnetic compass, In this study, in order to consider the drift angle due to external disturbance such as wind and wave, the course of ground( COG) can be used instead of heading at higher speed than a certain value, To test the performance of newly-designed WTA, the tests were carried out in actual sea area near Gwang-an bridge of Busan. In this paper, the sea trial test results from WTA are analyzed and compared with those from manual control and those from commercial controller.