• 한국항공운항학회지
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• 제20권2호
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• pp.58-63
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• 2012

An altitude chamber, also known as a hypobaric chamber, is a device used during aerospace or high terrestrial altitude research or training to simulate the effects of high altitude on the human body. Although data from altitude chamber researches using experimental animals have been accumulated, studies in the humans exposed to hypobaric conditions are seldomly reported. Despite the importance of altitude chamber flight training in the field of aviation physiology, the hematological analysis of post-flight physiological changes has rarely been performed. The aims of the present study were to investigate the alterations in blood components during altitude chamber flight and to determine whether the differences between pre- and post-flight values are significant. Sixty experienced pilots in the Republic of Korea Air Force were enrolled in the altitude chamber flight training. Venous blood samples were obtained before and immediately after the flight. Compared with the pre-flight values($6.32{\times}10^3/mm^3$, $5.02{\times}10^6/mm^3$, 15.61 g/dL, respectively), white blood cell count, red blood cell count and hemoglobin level were significantly increased after the flight($6.77{\times}10^3/mm^3$, $5.44{\times}10^6/mm^3$, 16.26 g/dL; p=0.006, p=0.012, p<0.001, respectively). These alterations may be attributable to the exposure to hypobaric hypoxia, 100% oxygen supply for denitrogenation, considerable rise and fall in altitude and psychophysical stress due to these factors. In further studies, experimental groups and methods should be individualized to ensure objectivity and diversification. In addition, multiple time-frame analyses regarding the changing pattern of each blood component are also required to elucidate the physiological process for adapting to the high terrestrial altitude exposure.

• 한국항공우주학회지
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• 제49권5호
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• pp.383-388
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• 2021

항공기에 사용되는 공기 흡입식 엔진은 고도가 높아질수록 성능의 한계를 가지며, 이는 실용상승한도(Service Ceiling)와 절대상승한도(Absolute Ceiling) 고도로 나타나게 된다. 고정익 항공기가 순항비행(Level Flight) 상태에서 고전제어기법(Classical Control)을 사용하여 고도 및 속도 유지를 하는 방법은 일반적으로 속도 증/감속을 위해 추력을 사용하고, 고도 증/감을 위해 피치 자세를 사용한다. 실용 상승 한도 고도 부근에서 이 방법을 사용하는 경우 고도 오차를 줄이기 위해 피치를 증가시키면 속도 감속으로 나타나게 된다. 따라서 피치 자세를 사용하여 속도를 먼저 유지하는 방법을 사용해야 한다. 특히 무인기의 경우 이 두 가지의 방법을 자동으로 적절한 시점에 사용할 수 있어야 한다. 본 논문에서는 고도 상승률이 둔화되는 실용상승한도 부근에서 속도와 고도유지 알고리즘의 전환 방법을 제안하고, 비행시험을 통해 개선된 효과를 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.590-593
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• 2005

Unmanned Helicopter has several abilities such as vertical Take off, hovering, low speed flight at low altitude. Such vehicles are becoming popular in actual applications such as search and rescue, aerial reconnaissance and surveillance. These vehicles also used under risky environments without threatening the life of a pilot. Since a small unmanned helicopter is very sensitive to environmental conditions, it is generally known that the flight control is very difficult problems. The nonlinear adaptive fuzzy controller design procedure and its applications for altitude control of unmanned helicopter were described in the paper. This research was concentrated on describing the design methodologies of altitude controller design for small unmanned helicopter acquiring autonomous take off and vertical movement. The design methodologies and performance of the altitude controller were simulated and verified with an adaptive fuzzy controller. Throughout simulation results, I showed that the proposed adaptive controllers have enhanced control performance such as robustness, effectiveness and safety, in the altitude control of the unmanned helicopter.

• 제어로봇시스템학회논문지
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• 제20권7호
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• pp.724-729
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• 2014

This paper presents the altitude control of a quadrotor system under the disturbance. The altitude is measured by an ultra sonic sensor attached at the bottom of the quadrotor system and the measured altitude data are used in the time-delayed controller. To test the robustness of the controller, a weight attached to the center of the system is dropped intentionally several times to cause disturbances to the system. Performances of the altitude control by the PID control and time-delayed control method are compared experimentally. Experimental studies are conducted to verify the outperformance of the time-delayed controller for controlling the altitude of the quadrotor system under disturbances.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1992년도 추계학술대회논문집
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• pp.9-17
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• 1992

To study on the guideline for high altitude training, physiological changes are considered. The recommanded is to deeply understand for altitude physiology, not to exposure at high for elite athlete, to climb progressively and to train at 3000 .approx. 5300m. Steady altitude exposures should be limited to periods of 2 to 4 weeks. During the training, the intermittent sea level or extremely high trips should be scheduled. It is expected that this study would be contributed to sport trainer, athlete and climber.

• Journal of Astronomy and Space Sciences
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• 제31권1호
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• pp.33-39
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• 2014

This paper describes an experimental approach to evaluate the effective doses of space radiations at high-altitude by combining the measured data from the Liulin-6K spectrometer loaded onto the air-borne RC-800 cockpit and the calculated data from CARI-6M code developed by FAA. In this paper, 15 exposed dose experiments for the flight missions at a high-altitude above 10 km and 3 experiments at a normal altitude below 4 km were executed over the Korean Peninsula in 2012. The results from the high-altitude flight measurements show a dramatic change in the exposed doses as the altitude increases. The effective dose levels (an average of $15.27{\mu}Sv$) of aircrew at the high-altitude are an order of magnitude larger than those (an average of $0.30{\mu}Sv$) of the normal altitude flight. The comparison was made between the measure dose levels and the calculated dose levels and those were similar each other. It indicates that the annual dose levels of the aircrew boarding RC-800 could be above 1 mSv. These results suggest that a proper procedure to manage the exposed dose of aircrew is required for ROK Air Force.

• 신재생에너지
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• 제7권2호
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• pp.36-42
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• 2011

The wind speed at the altitude around 300 m is much higher and less variable than at the altitude around 80 m which is the same height of the MW class tower turbine's hub height. The wind power density is increased 0.37 W/$m^2$ per meter at the altitude around 6 to 7 km and 0.25 W/$m^2$ per meter at the altitude around 80 to 500 m. There are two types of power generation systems using lifting bodies. The one is that The generator is installed in the ground station and stretched into the lifting body through the tether. The other is that the generator is installed in the lifting body and stretched into the ground station through the tether. Many kinds of lifting bodies are also researched in the world, called kites, wings, single or twin aerostat, and so on. This article introduced the technical development status and the market prospects of the high altitude wind power generation system all over the world in detail.

• 한국항행학회논문지
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• 제9권2호
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• pp.87-92
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• 2005

본 연구에서는 산업용 무인 헬리콥터의 자율비행을 위한 일환으로 퍼지 제어기를 이용하여 고도제어를 하였다. 본 논문에서는 가솔린 엔진을 사용하는 전장 3m급의 무인 헬리콥터를 설계하고 이의 재원을 이용하여 Takagi-Sugeno-Kang 형의 퍼지 제어기법으로 고도 제어기를 구성하였다. 목표 고도값과 고도의 오차, 그리고 속도를 이용하여 입력 선형 맴버쉽 함수를 생성하였다. 이렇게 구성된 멤버쉽 함수를 이용 제어입력을 생성하였고, 생성된 제어입력을 이용하여 메인 로터의 피지를 제어하고 그 결과를 이용하여 속도와 고도를 구하였다. 시뮬레이션을 통하여 설계한 퍼지제어기의 고도제어 성능을 평가하였다.

• ETRI Journal
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• 제45권2호
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• pp.240-253
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• 2023

Spatial information is geometrical information combined with the properties of an object. In city areas where unmanned aerial vehicle (UAV) usage demand is high, it is necessary to determine the appropriate driving altitude considering the height of buildings for safe driving. In this study, we propose a data-provision method that generates the driving altitude of UAVs with a pseudo-3D building model. The pseudo-3D building model is developed using high-precision spatial information provided by the National Geographic Information Institute. The proposed method generates the driving altitude of the UAV in terms of tile information, including the UAV's starting and arrival points and a straight line between the two points, and provides the data to users. To evaluate the efficacy of the proposed method, UAV driving altitude information was generated using data of 763 551 pseudo-3D buildings in Seoul. Subsequently, the generated driving altitude data of the UAV was verified in AirSim. In addition, the execution time of the proposed method and the calculated driving altitude were analyzed.

• BMB Reports
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• 제40권3호
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• pp.426-431
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• 2007

To investigate the possible mechanisms of high-altitude native animals in adapting to high altitude, we cloned hemoglobin alpha-chain (alpha-chain Hb) gene from Pantholops hodgsonii, an animal species that indigenously lives at elevations of 3700-5500 m on the Qinghai-Tibetan plateau. Using reverse transcription polymerase chain reaction (RT-PCR) technique, the alpha-chain Hb gene was amplified from total RNA in the liver of the Pantholops hodgsonii. TA cloning technique was used and the PCR product was cloned into pGEM-T vector. The DNA sequence of the gene was highly homologous with sheep (99.1%), goat (98.6%), cattle (95.6%) and human (86.5%). The alpha-chain Hb gene encoded a 142-amino acid protein that could be identified with the homology of alpha-chain Hb protein in sheep (98%), goat (96%), cattle (91%) and human (87%). However, 18 alternations were detected when compared with the alpha-chain Hb gene in human, and 2 in sheep. Moreover, the alterations of a117 GluAsp and $\alpha$132 AsnSer in important regions were noted in human and sheep, respectively. Phylogenetic analysis suggested that the structure of alpha-chain Hb was highly similar to that in sheep. This study provided essential information for elucidating the possible roles of hemoglobin in adapting to extremely high altitude in Pantholops hodgsonii.