• Journal of Veterinary Clinics
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• v.24 no.1
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• pp.1-4
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• 2007

Despite the risk of high altitude disease (HAD), raising cattle at higher altitudes does have advantages such as beef quality due to minimal chance of infection and stress. The ideal situation is to determine the optimum altitude suitable for raising cattle while at the same time minimizing the risk of HAD. Therefore, in this study, we documented the health status of three groups of steers, raised at three different altitudes (200m, 400m and 800m) in Gangwon province, using routine hematological, biochemical and hormonal tests. The red blood cell counts and hemoglobin concentration were highest in the 800m group, and lowest in the 200m group, possibly due to hypoxia induced myeloid and erythroid stimulation. The mean concentration of AST, BUN and serum cortisol were lowest in the 800m. These findings suggest the stress factor will contribute the general health status of animal and indicate a difference in the Hanwoo groups raised at 800m compared to 200m, where the cattle raised at the higher altitude exhibit better health status compared to the lower altitude, possibly due to less stressful environment in the higher altitude.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.994-1002
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• 2008

In this paper a novel tracking system is described, regarding the influence of shadow between array, aimed at improving the efficiency of PV tracking system. Comparing with a building site versus capacity power, domestic solar powers have a limited siting. Therefore, each array interferes with the shadow of other arrays. The loss by influence of those shadow can be compensated for by means of control algorithm of the tracking device. The paper suggests a method controlling an altitude for length which is received the shadow influence of PV array. By using an azimuth of current solar position and the length between arrays, the controller of tracking device is able to calculate the length between actual arrays and make a comparison of the shadow length at a specific time with the length between arrays. When the shadow length is longer than the length between arrays, the controller of tracking device can adjust a position by compensating error altitude of the length between arrays at an altitude of current solar position. In the paper, we develop the control algorithm able to minimize the loss caused by the influence of shadow on the PV tracking system, and compared this with conventional output system. The controller has been tested in the laboratory with proposed algorithm and shows excellent performance.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.777-781
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• 2001

An Altitude Engine Test Facility(AETF) was built at the Korea Aerospace Research Institute in October 1999 and has been being operated for altitude testing of the gas turbine engines of 3,000 Ibf class or less. The AETF has been calibrated using several engines such as J69 engine of Teledyne Co. as a facility checkout engine. Based on the test results, uncertainty analyses on the air flow rate and thrust were performed according to ASME PTC 19.1-1998. As the analyses showed that the level of uncertainty was not satisfactory over the whole operating envelop, several modifications of the facility and testing method were made in order to improve the measurement uncertainty. As a result, the uncertainty of the air flow measurement was improved by 0.1 % over all the test conditions, and the net thrust measurement by upto 3%. The improved measurement uncertainties of air flow and thrust are 0.68-0.73% and 0.4-1.3%, respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.1
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• pp.43-50
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• 2007

In this study, Hybrid Separate Learning Algorithm(SLA) consisting of Support Vector Machine(SVM) and Artificial Neural Network(ANN) has been used for developing the defect diagnostic algorithm of the aircraft turbo-shaft engine in the off-design range considering altitude variation. Although the number of teaming data and test data highly increases more than 6 times compared with those required for the design condition, the proposed defect diagnostics of gas turbine engine using SLA was verified to give the high defect classification accuracy in the off-design range considering altitude variation.

• The Korean Journal of Ecology
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• v.15 no.4
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• pp.329-335
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• 1992

Bionomics of diplopodes was studid near chongyongchi in the chiri mountains from sept. 1990 to dec. 1991 by surveying 10 sample sites at 12 occasions. During this period 13 species of diplopodes from 11 genera, 8 families, and 6 orders were collected. Species were more diversed under quercus mongolica followed by quercus serrata and pinus densiflora sp. epenerchodus koreanus bifidus, and e. k. koreanus were found in all sample sites and these 6 species have been reported to be distributed throughout south korea. yamasinaium sp., riukiaria semicirculalis, parafontaria koreanus, and sicotanus eurygaster were found only under quercus mongolica community and postulated to be related to diet meanwhile other enviromental factors such as temperature, soil ph, and altitude should be taken into consideration. Species diversity index was higher at altitude 700m followed by at 900m, 1, 000m, 800m, 600m, 500m, 1, 100m, 400m, 300m, and 1, 200m in discending order likely due to the enviromental factors such as climatic and edaphic affects, disturbance by human, and degree of floral diversity. Species similarity index was highest 0.78 between altitude 500m and 600m sample sites could be grouped into 3, namely first 300m, 400m, second 500m, 600m, 700m, 1, 000m, 800m, 900m, and third 1, 100m, 1, 200m.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.10
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• pp.1017-1025
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• 2008

The air data system(ADS) was developed for unmanned aerial vehicle(UAV) in this paper. Generally, the ADS helps flight control computer(FCC) to control the UAV above the stall speed and to hold the given altitude. The accurate measurement of airspeed and altitude of UAV is important because it indicates a flight performance and assures a safe flight. The ADS consists of MEMS pressure sensors, a lowpass filter, a micro controller unit and a pitot-tube. The ADS errors were reduced by pressure and temperature compensation of MEMS sensors. Finally, the altitude and airspeed data of the ADS was compared with GPS data in the flight test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.6
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• pp.51-56
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• 2005

This paper introduces an altitude determination algorithm using GPS/INS/Baroaltimeter and evaluates the algorithm by real field tests. The test results show that the proposed method can determine the altitude of an aircraft continuously and sensitively. Therefore, it is appropriate to be used as an altimeter for a flight control system, especially for the automatic take-off and landing. In addition, it is shown that the second and the third baro-inertial vertical channel damping methods are essentially complementary filters while the proposed scheme improves these complementary filters.

• Korean Journal of Remote Sensing
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• v.33 no.1
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• pp.15-24
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• 2017

Jellyfish (cnidarian) are conspicuous in many marine ecosystems when in bloom. Despite their importance for the ecosystem structure and function, very few sampling programs are dedicated to sample jellyfish because they are patchily distributed and easily clogged plankton net. Although satellite remote sensing is an excellent observing tool for many phenomena in the ocean, their uses for monitoring jellyfish are not possible due to the coarse spatial resolutions. Hence, we developed the low altitude remote sensing platform to detect jellyfish in high resolutions, which allow us to monitor not only horizontal, but also vertical migration of them. Using low altitude remote sensing platform,we measured the jellyfish from the pier at the Chesapeake Biological Laboratory in Chesapeake Bay. The patterns observed included discrete patches, in rows that were aligned with waves that propagated from deeper regions, and aggregation around physical objects. The corresponding areas of exposed jellyfish on the sea surface were $0.1{\times}10^4pixel^2$, $0.3{\times}10^4pixel^2$, and $2.75{\times}10^4pixel^2$, respectively. Thus, the research result suggested that the migration of the jellyfish was related to the physical forcing in the sea surface.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.75-81
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• 2006

The propulsion system of KSLV-I second stage is engine with high expansion ratio and its starting altitude is high. To verify the performance of engine before the launch in the ground, high altitude test facility to simulate its operating condition is necessary. This material is about the concept design of high altitude simulation test facility for second stage engine. And it will be the basis for the construction of test facility and the test of engine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.373-376
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• 2009

A full rig combustor test and altitude ignition test were carried out for radial-annular combustor of micro turbojet engine. 11.2% total pressure loss and 99.85% of combustion efficiency were measured at design point of engine under sea level standard condition and $2{\sim}6$ of air excess ratio for ignition envelope was achieved on engine starting regime. Finally, A 30,000 ft high altitude ignition test was also performed and finally we found out that the developed radial-annular combustor is appropriate to micro turbojet engine.