• 지역사회간호학회지
• /
• 제18권2호
• /
• pp.211-222
• /
• 2007

Purpose: This study was conducted to identify relations among health behaviors, health symptoms and physical fitness of people in the same community. Method: The study was designed as a descriptive survey and the participants were 1,621 healthy people. Data were collected from March to December, 2003 using a structured questionnaire on health behaviors, health symptoms and physical fitness. Data were analyzed by descriptive statistics, $\chi^2$-test, t-test, two-way ANOVA, Pearson correlation coefficients and multiple regression using SPSS/PC. Results: The result of multiple regression showed that sex, age, and BMI were related to physical fitness. In health-related physical fitness, regular exercise was related to cardiorespiratory endurance and flexibility, and daily caffeine intake was related to muscular endurance. In performance-related physical fitness, having breakfast regularly was related to power, daily caffeine intake was related to agility, and regular lifestyle and health symptoms were related to balance. Conclusion: In conclusion, this study suggests that for better physical fitness, nursing strategies and intervention programs should include physical fitness-related factors, and education programs should be developed based on the above parameters to promote positive perception of physical fitness.

• International Journal of Aeronautical and Space Sciences
• /
• 제9권2호
• /
• pp.64-70
• /
• 2008

The UAV propulsion system that will be operated for long time at more than 40,000ft altitude should have not only fuel flow minimization but also high reliability and durability. If this UAV propulsion system may have faults, it is not easy to recover the system from the abnormal, and hence an accurate diagnostic technology must be needed to keep the operational reliability. For this purpose, the development of the health monitoring system which can monitor remotely the engine condition should be required. In this study, a fuzzy trend monitoring method for detecting the engine faults including mechanical faults was proposed through analyzing performance trends of measurement data. The trend monitoring is an engine conditioning method which can find engine faults by monitoring important measuring parameters such as fuel flow, exhaust gas temperatures, rotational speeds, vibration and etc. Using engine condition database as an input to be generated by linear regression analysis of real engine instrument data, an application of the fuzzy logic in diagnostics estimated the cause of fault in each component. According to study results. it was confirmed that the proposed trend monitoring method can improve reliability and durability of the propulsion system for a long endurance UAV to be operated at medium altitude.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
• /
• pp.87-90
• /
• 2007

장기 체공 무인 항공기를 위한 연료 전지 동력 시스템을 개발하였다. 기존의 고압 수소 저장 방식의 문제점을 해결하기 위해 높은 에너지 밀도를 갖는 액상의 화학 수소화물을 연료로 사용하였다. 수소화물을 전환하여 수소를 발생하는 연료 공급 장치는 촉매 반응기, 펌프, 연료 카트리지, 분리기, 제어기로 구성되어 있으며, 전력을 발생하기 위한 연료전지 스택과 함께 연료 전지 동력 시스템을 무인 항공기에 탑재하였다. 연료 전지 동력 시스템을 무인 항공기에 적용하기 위한 성능 검증을 수행하였다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.444-449
• /
• 2004

The design modification of bottom guide structures of the instrumented capsule, which is used for the irradiation test in the HANARO reactor, was required because of the trouble of the bottom guide arm's pin during irradiation. The previous structure with 3-pin arms was changed into the cone shape of one body. The specimens of the bottom end cap ring with three different sizes (${\Phi}68/70/72mm$) were designed and manufactured. The out-pile tests for the capsule with previous and new three bottom guide structures were performed in the one-channel flow test facilities. In order to evaluate the compatibility with HANARO and the structural integrity of the capsule, a loading/unloading, a pressure drop, a thermal performance, a vibration, and an endurance test were conducted. From out-pile test results, the capsule with the cone shape bottom guide structures was found to be more stable than the previous structure and the optimized size of the bottom guide structure selected was 70mm in diameter. It is expected that the new bottom guide structures will be applicable to all material and special capsules which will be designed and manufactured for the irradiation tests in the future.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2008년 영문 학술대회
• /
• pp.84-88
• /
• 2008

The UAV propulsion system that will be operated for long time at more than 40,000ft altitude should have not only fuel flow minimization but also high reliability and durability. If this UAV propulsion system may have faults, it is not easy to recover the system from the abnormal, and hence an accurate diagnostic technology must be needed to keep the operational reliability. For this purpose, the development of the health monitoring system which can monitor remotely the engine condition should be required. In this study, a fuzzy trend monitoring method for detecting the engine faults including mechanical faults was proposed through analyzing performance trends of measurement data. The trend monitoring is an engine conditioning method which can find engine faults by monitoring important measuring parameters such as fuel flow, exhaust gas temperatures, rotational speeds, vibration and etc. Using engine condition database as an input to be generated by linear regression analysis of real engine instrument data, an application of the fuzzy logic in diagnostics estimated the cause of fault in each component. According to study results, it was confirmed that the proposed trend monitoring method can improve reliability and durability of the propulsion system for a long endurance UAV to be operated at medium altitude.

• 한국융합학회논문지
• /
• 제10권4호
• /
• pp.195-201
• /
• 2019

유산소성 운동수행능력의 필드테스트로 대표되는 셔틀런 테스트와 요요테스트를 최대산소섭취량 및 다른 주행테스트들과 비교 검토함으로써 대학 축구선수들의 심폐지구력을 평가하는 유효한 필드테스트를 제안하는 것을 목적으로 하였다. 셔틀런 테스트는 휴식구간이 없이 지속적으로 달려야 하는 반면 요요 테스트의 경우 휴식구간이 설정되어 있어 휴식기를 활용하여 컨디션을 조절하며 주행한다는 특성이 있다. 따라서 요요테스트는 주행과 회복을 반복하는 간헐적 운동을 주로 하는 축구선수들의 종목 특성을 고려한 심폐기능 평가 시 보다 효율적인 현장검사로 활용될 수 있을 것이다.

• 항공우주시스템공학회지
• /
• 제15권4호
• /
• pp.11-20
• /
• 2021

The estimation of hovering flight time of multicopters using the battery power propulsion system is important for the development and design of the aircraft and its operation. For a given operational weight, the maximum possible battery weight can be decided using both a conventional energy density method and a new Peukert law. In the present study, the hovering flight time is predicted using both methods. The specific data of multicopters in the published literatures were employed for the computation of the hovering flight time. The results were validated with the measured data. The effect of figure of merit of propeller, battery discharging process on the hovering flight time was evaluated, Finally, the effect of the battery cell and package connection types on the hovering time was investigated. It was found that the combination of serial battery cell connections and parallel package connection is the bast in the endurance maximization aspect. As the cell number increases in a package, the hovering flight time is increased. There exists the max. battery ratio for the given takeoff gross weight.

• 한국군사과학기술학회지
• /
• 제25권5호
• /
• pp.539-544
• /
• 2022

This research shows the test performance of a 6 kW-scale hybrid electric power system for the high endurance drone. The power system is composed of a two-stroke reciprocal engine, starter-generator and battery, and they are integrated as one power unit. The engine is designed to provide the house for holding the starter-generator at the end of a crankshaft in turn the engine and starter-generator can maintain the same speed during the operational period. In this way, the generated power is readily controlled by just manipulating an engine throttle movement. Moreover, the starter-generator can initiate an engine operation with an aid of battery power until the combustion process becomes stabilized. In consequence, integration mechanism between an engine and generator is simplified, which results in weight reduction achieved. The duty of back-up battery is to provide a starting power to generator via a system controller in addition to covering momentarily power shortage. Therefore, the electric power system is vindicated to provide 6 kW power through a ground test.

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2003년도 춘계학술대회 논문집
• /
• pp.88-88
• /
• 2003

n view of the role of haptoglobin as a candidate for physical performance, we investigated the protein polymorphism of the haptoglobin in elite Korean male athletes. The serum sample was collected from 120 Korean male eliteathletes. The haptoglobin phenotypes were determined by polyacrylamide gel electrophoresis, followed by peroxidase staining. (omitted)

• Tribology and Lubricants
• /
• 제15권1호
• /
• pp.108-115
• /
• 1999

The electrical and frictional properties of oil-impregnated sintered-metal bearing (OSB) and herringbone-grooved fluid bearing (HFB) with varying loads and speeds were measured. OSB shows very good performance up to 20,000 rpm and 0.05 N, and HFB successfully works up to 35,000 rpm and 0.05 N. From the endurance tests on start-stop and continuous operation, it was confirmed that those bearings could be mass-produced fur use on scanner motor in a laser scanner unit.