• 한국전자파학회논문지
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• 제29권8호
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• pp.640-647
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• 2018

본 논문은 전투기 레이다의 표적 추적정확도(추적오차)를 분석하는 방법에 대한 연구이다. 레이다 측정 시 발생하는 측정오차, 탐지실패, radar cross section(RCS) 요동은 측정 품질을 열화시키며, 이는 추적정확도에 영향을 미치는 요인이 될 수 있다. 따라서 정확한 추적성능분석을 위해 이러한 레이다 측정 특성을 고려하는 것이 필요하다. 본 논문에서는 측정오차, 탐지확률, RCS 요동과 같은 레이다 특성을 복합적으로 활용하여 추적정확도를 분석하는 방법에 대해서 제안한다. 제안한 분석 방법을 활용한 실험을 통해 탐지확률과 RCS 요동에 의한 추적정확도 열화를 확인할 수 있었다.

• International Journal of Fluid Machinery and Systems
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• 제5권2호
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• pp.91-99
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• 2012

The Fighter aircraft transmission system consists of a light weight, High Speed Flexible Coupling (HSFC) known as Power Take-Off shaft (PTO) for connecting Engine gearbox (EGB) with Accessory Gear Box (AGB). The HSFC transmits the power through series of specially contoured metallic annular thin flexible plates whose planes are normal to the torque axis. The HSFC operates at high speed ranging from 10,000 to 18,000 rpm. The HSFC is also catered for accommodating larger lateral and axial misalignment resulting from differential thermal expansion of the aircraft engine and mounting arrangement. The contoured titanium alloy flexible plates are designed with a thin cross sectional profile to accommodate axial and parallel misalignment by the elastic material flexure. This paper investigates the effect of misalignment on the transmission characteristics of the HSFC couplings. A mathematical model for the HSFC coupling with misalignment has been developed for analyzing the torque transmission and force interaction characteristics. An extensive testing has been conducted for validating characteristics of the designed coupling under various misalignment conditions. With this the suitability of the model adapted for the design iteration of HSFC development is validated. This method will reduce the design iteration cycles of HSFC and can be extended for the similar development of flexible couplings.

• 한국경영과학회지
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• 제39권2호
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• pp.37-48
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• 2014

Fighter squadron flight scheduling is the integrated air operation plan that is an important role for improving pilot's flight skill and maintaining combat readiness by efficient using available all air resources including pilot, aircrafts, air-weapons, fuel and supporting facilities etc. Korea airforce, however, has a limit as to an effective flight operation due to manual flight scheduling with scheduler's own experience and intuition. Therefore, in our study, we propose the optimization model of flight scheduling based on mixed integer programming. This model includes several constraints of realistic and essential quantified data related with flight schedule and can assign appropriate pilots optimally which are distinctive three type's solutions : flight, alert and duty crew schedules. Proposed solution method can be improved pilot's capability and allocated further air resources systematically and efficiently. In addition, it can be reduced a workload of flight scheduler and minimized obstructed factors of flight safety. Finally, we demonstrate the experiment's results for the check of efficiency and validity of this model.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.527-530
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• 2010

전투기에 장착되는 정보수집용 포드의 냉각 장치인 ACM에 대한 성능 시험평가를 수행하였다. 시험평가 대상인 ACM은 역 브레이튼 공기 사이클로 작동되는 터보기기로서, 항공기의 비행속도에 의한 램 공기를 에너지원으로 사용하여 추가적인 에너지의 공급 없이 냉각 기체를 발생시킨다. 또한 습기에 민감한 전자장비의 냉각에 이용하기 위하여 열교환기를 함께 구성하였다. 성능시험을 통하여 개발 대상 ACM 및 열교환기는 요구 성능을 만족함을 확인하였다.

• 대한가정학회지
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• 제37권11호
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• pp.75-83
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• 1999

To develope an efficient fire fighter’s uniform for the fire fighting work and body protection, this study examined the regulations of fire lighter’s uniform and surveyed the actual wearing conditions, satisfaction degree, preferred color and design others. The results are as follows; 1. As for the satisfaction degree, the degree was normal in ordinary, low in working uniform and heat-proof uniform and very low in water-proof uniform about its design, size, color and materials. 2. As for the color, red was preferred for the working uniform and water-proof uniform. Blue, yellow and green was preferred next for corking uniform and yellow and blue for water-proof uniform. 3. As for the design, fire fighters wanted partial revision of the present uniform. They preferred stretchy training wear style and overact style in order. For the water-proof uniform, they preferred hip-length suit and pants and next to it they liked flee-length suit, waist belt and overact in order. 4. As for the regulations of the uniform, they wanted some addition in casual uniform, water-proof pants and water-proof gloves, and some deletion in the thermal barrier of water-proof uniform and ordinary uniform. 5. As for the distribution of the uniforms, the use of coupons was highly preferred.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.647-652
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• 2016

To reduce drag force at supersonic speeds, sharp leading edge is hugely efficient. It is, however, incompatible with leading edge shape to have fine aerodynamic characteristics at subsonic and transonic speeds. It is critical to reduce drag force for enhanced cruise performance and higher efficiency. An air superiority fighter, however, required to have high maneuverability for survivability, and sharp leading edge is not proper. Consequently, variable leading edge is demanded to reduce drag force significantly at supersonic speeds for cruise performance. Leading edge altering system is constructed with rigid material to improve possibility of realization, and minimized movement of its components in altering for reduce effects on flight. It is compared with bi-convex airfoil and NACA 65-006 airfoil, which have comparable maximum thickness. At Mach number 1.7 and zero angle of attack, supersonic mode of designed airfoil indicates approximately 17% higher drag coefficient than the bi-convex airfoil indicates, it is, however, 23% lower than the NACA 65-006 indicates. Also, subsonic mode of the designed airfoil shows fine aerodynamic characteristics in comparison with NACA 65-006 airfoil in subsonic and transonic speed range. In this regard, design of the airfoil achieved the object of this study satisfactorily.

• 한국군사과학기술학회지
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• 제17권2호
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• pp.189-196
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• 2014

Automated design program using commercial process integration and optimization program was developed for conceptual design of fighter-class aircraft. Wind tunnel test data and performance analysis results were compared for the verification of analysis tool of this program, and the usefulness of the tool was found. After integration with radar cross section analysis tool, the correlation with configuration design variables of wing, tail and performance parameters was identified by design of experiment, and the optimized configuration for weight and RCS was derived from optimization of empty weight and average frontal RCS value. After parameter definition of fuselage, the program can be implemented for full aircraft configuration.

• 한국군사과학기술학회지
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• 제24권5호
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• pp.467-474
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• 2021

A study on optimal shape selection of a mechanical fastening for the repair of crack defect of ROK Air Force F-5 fighter wing was conducted. The crack defect occurred in the spar of the wing, and the technical manual does not specify the repair method. However, ROK Air Force decided to develop a repair technology for this defect in consideration of various logistic conditions. Three repair shapes for the proper repair were devised and the finite element analysis was performed to examine the structural safety of these three connection members. As a result of the structural safety review, two connection members except one were structurally safe with safety margins over zero because the calculated stress values were at or below the yield strength level. Therefore, two connection members were determined to be able to use for repair under the condition that the aircraft operated within the design limit load. The results of this study would be very useful if the same defect occurs in long-term aircraft operated by the ROK Air Force.

• 한국항공운항학회지
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• 제26권4호
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• pp.116-121
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• 2018

According to the incresement of aging aircraft, Republic of Korea Air Force (RoKAF) conducted a teardown inspection of aircraft's EWIS (electrical wiring interconnection system) to determine the status of deterioration and the influence of failure occurrences due to it. The inspected aircraft were the retired fighter jets that had been used for more than 40 years. By analyzing defect type and the defect tendency, RoKAF can establish the necessary measures for the usage extension of their fleet and furthermore, the analysis results can be used as a basic data for the preparation of it's aircraft aging. EWIS inspection was done throughout careful visual inspection technique by removing all the ducts and pipes located in the fuselage and wings. For the aircraft wiring where no damage was found, the elongation tests were performed to determine the deterioration of wiring according to the location of the aircraft. The connectors, which is the main cause of intermittent failure, were completely disassembled and inspected for internal damage such as corrosion, abrasion, and traces of foreign objects. The detected defects were classified into 4 severity levels based on the type of damage, and the classified defects were weighted according to the criticality which may affects to it's system to establish the action plan.

• 한방재활의학과학회지
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• 제31권4호
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• pp.13-23
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• 2021

Objectives The purpose of this research is to comprehensively analyze about Jowiseungcheong-tang (Diàowèishēngqīng-tāng). This herbal medicine is widely used to treat obesity and metabolic disease. Methods We used 3 search terms, 'Jowiseungcheong-tang', 'Jowiseungcheong-tang plus obesity' and 'Jowiseungcheong-tang plus metabolic disease' in Korean word via 5 domestic databases. Therefore, 8 laboratory experiments and 4 clinical researches were chosen. Results Jowiseungcheong-tang (Diàowèishēngqīng-tāng) was identified as a herbal medicine for obesity and related metabolic disease. In plasma level of lipid, leptin, inflammatory material were decreased in laboratory experiments. Weight loss and symptom relief were reported in clinical research. Conclusions Definite information about laboratory experiment was showed, specifically suitable index and numerical value. In clinical research, although Jowiseungcheong-tang (Diàowèishēngqīng-tāng) is widely used for obesity and metabolic disease, the number of reported thesis and patient were pretty a few. Also, diagnosis methods were also scanty. Multi-institutional clinical trial should be progressed.