• 제목/요약/키워드: Air Force

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비행장갑설계를 위한 사용실태분석 및 개선안 개발 (Usage Analysis and Design Development for Pilot Gloves)

  • 박지은;전은진;정정림;박세권;유희천;김희은
    • 한국의류산업학회지
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    • 제11권5호
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    • pp.764-770
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    • 2009
  • This study was conducted to analyze the wearing condition on gloves for pilots and to suggest the developments for pilot gloves design. This survey was performed with 99 pilots and the questionnaires included items about discomfort, materials and problems when wearing pilot gloves. The respondents felt uncomfortable on the finger tip, the hollow area of the hand and the end of thumb when they move their hands with the gloves. They replied that the finger length, palm length, and circumference of the fingers did not match well. Also they complained there was severe abrasion in the tip of the thumb, finger tips and the middle of the palm of the gloves. The result of these analyses supports the following suggestions. It is necessary to improve durability by applying the additional materials to the severely worn parts. Punching on the glove materials could improve sweat rate and ventilation, and careful washing should be accompanied to prevent the occurrence of linters and transformation after laundering. And it is needed to prepare an accurate and more diversified size system and to design the gloves fitted to the individual hands. With these in mind, it is required to propose solutions for pilot gloves with reference to the survey results in order to design appropriate pilot gloves in terms of movement, size and material. It was concluded that an analysis of the wearing condition and developments are useful for ergonomics pilot gloves design.

Dynamic Stereo PIV에 의한 델타형 날개에서의 3차원 와류 유동에 관한 연구 (Three Dimensional Vortex Behavior of LEX Delta Wing by Dynamic Stereo PIV)

  • 이현;김미영;최장운;최민선;이영호
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2003년도 추계학술대회 논문집
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    • pp.39-42
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    • 2003
  • Leading edge extension(LEX) in a highly swept shape applied to a delta wing features the modern air-fighters. The LEX vortices generated upon the upper surface of the wing at high angle of attack enhance the lift force of the delta wing by way of increased negative suction pressure over the surfaces. The present 3-D stereo PIV includes the Identification of 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criterion and so on. A delta wing model with or without LEX was immersed in a circulating water channel. Two high-resolution, high-speed digital cameras$(1280pixel\times1024pixel)$ were used to allow the time-resolved animation work. The present dynamic stereo PIV represents the complicated vortex behavior, especially, in terms of time-dependent characteristics of the vortices at given measuring sections. Quantities such as three velocity vector components, vorticity and other flow information can be easily visualized via the 3D time-resolved post-processing to make the easy understanding of the LEX effect or vortex emerging and collapse which are important phenomena occurring in the field of delta wing aerodynamics.

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규칙적 운동과 제2형 당뇨병 발생에 관한 전향적 코호트 연구 -공복혈당장애군을 대상으로- (A Prospective Cohort Study of Exercise and the Incidence of Type 2 Diabetes in Impaired Fasting Glucose Group)

  • 엄홍대;이덕철;이상이;김연수
    • Journal of Preventive Medicine and Public Health
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    • 제41권1호
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    • pp.45-50
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    • 2008
  • Objectives : To determine the relationship between exercise and the incidence of type 2 diabetes in an impaired fasting glucose group. Methods : This prospective cohort study was conducted in 19,440 men and 4,297 women, aged 30-69 years, with impaired fasting glucose at baseline who had undergone biennial medical evaluation through the National Health Insurance Corporation from 2000 to 2004. Impaired fasting glucose was defined as fasting glucose of 100 to 125 mg/dl and the subjects were divided into 3 groups depending on weekly exercise frequency. Multivariate logistic regression analysis was used to evaluate the association between the baseline exercise status and incidence of type 2 diabetes. Results : During the 4-year follow-up, a total of 3,239 men and 283 women developed type 2 diabetes, a cumulative incidence of 16.6% for men, and 6.5% for women. Also, 1,688 men (21.2%) and 127 women (15.2%) developed type 2 diabetes in the obese group. The adjusted relative risk (RR) of developing type 2 diabetes in non-exercising men was significantly higher than exercising men regularly (RR= 1.375, 95% CI=1.236-1.529)(p<0.0001), and the RR for non-exercising women was higher than exercising women regularly (RR=1.124, 95% CI=0.711-1.778). The RR for non-exercise men/women in the obese group was 1.571 (95% CI=1.351-1.827)(p<0.0001)/1.869 (95% CI=0.846-4.130). Conclusions : Regular exercise is effective in preventing type 2 diabetes in people with impaired fasting glucose, and particularly in obese people. People with risk factors for diabetes should participate in a regular exercise program.

측면 절개된 판형 스프링으로 지지된 경수로 연료봉 진동의 실험적 고찰 (An Experimental Study on the Vibration of the PWR Fuel Rod Supported by the Side-sloted Plate Springs)

  • 최명환;강흥석;윤경호;송기남
    • 한국소음진동공학회논문집
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    • 제13권10호
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    • pp.798-804
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    • 2003
  • One of the methods that are used to compare and verify the supporting performance of the spacer grids developed is the vibration characteristic test. A modal test in this paper is performed for a dummy rod 3,847 mm tall supported by eight New Doublet (ND) spacer grids. For the vibration test in air, nine accelerometers, one displacement sensor and one shaker are used for acquiring signals, and an I-DEAS TDAS software Is employed for analyzing the signals. Also, a finite element (FE) analysis is performed by a beam-spring simple model and a contact model simulating the contact phenomenon between the rod and the ND spring. And then, the results of the modal testing are compared with those of the FE analysis. The natural frequencies as well as the mode shapes obtained by the experiment have a greater similarity to the results by the contact model than the previous beam-spring model. In audition, for grasping whether or not the modal parameters are influenced by where shaking spot is, two kinds of tests are performed : one is for the shaker attached at the fourth span (center), the other is for the shaker at the fifth span that is one span nearer to the bottom of the rod. The latter shows higher MAC than the former Finally, the vibration displacements are measured in the range of 0.l12∼0.214 mm for the excitation force of 0.25∼0.75 N.

Effect of Sintering Temperature on the Micro Strain and Magnetic Properties of Ni-Zn Nanoferrites

  • Venkatesh, D.;Siva Ram Prasad, M.;Rajesh Babu, B.;Ramesh, K.V.;Trinath, K.
    • Journal of Magnetics
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    • 제20권3호
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    • pp.229-240
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    • 2015
  • In this study, nanocrystalline ferrite powders with the composition $Ni_{0.5}Zn_{0.5}Fe_2O_4$ were prepared by the autocombustion method. The obtained powders were sintered at $800^{\circ}C$, $900^{\circ}C$ and $1,000^{\circ}C$ for 4 h in air atmosphere. The as-prepared and the sintered powders were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and magnetization studies. An increase in the crystallite size and a slight decrease in the lattice constant with sintering temperature were observed, whereas microstrain was observed to be negative for all the samples. Two significant absorption bands in the wave number range of the $400cm^{-1}$ to $600cm^{-1}$ have been observed in the FT-IR spectra for all samples which is the distinctive feature of the spinel ferrites. The force constants were found to vary with sintering temperature, suggesting a cation redistribution and modification in the unit cell of the spinel. The M-H loops indicate smaller coercivity, which is the typical nature of the soft ferrites. The observed variation in the saturation magnetization and coercivity with sintering temperature has been attributed to the role of surface, inhomogeneous cation distribution, and increase in the crystallite size.

무인기 군집 비행 보안위협 및 보안요구사항 연구 (A study on the security threat and security requirements for multi unmanned aerial vehicles)

  • 김만식;강정호;전문석
    • 디지털융복합연구
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    • 제15권8호
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    • pp.195-202
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    • 2017
  • Unmanned Aerial Vehicle (UAV)는 군사적 목적으로 주로 이용되었지만 ICT의 발전과 저렴해진 제작비용으로 인해 다양한 민간 서비스에서도 점차 이용되고 있다. UAV는 앞으로 스스로 임무를 수행하는 자율비행을 할 것이라 기대되고 있는데, 복잡한 임무를 수행하기 위해서는 군집 비행이 필수적이다. UAV 군집 비행은 기존 UAV 시스템과 네트워크 및 인프라 구조가 달라 국내외에서 많은 연구가 이루어지고 있지만, 아직 안전한 UAV 군집 비행을 위한 보안위협 및 보안요구사항에 대한 연구가 이루어지지 않고 있다. 본 논문에서는 이러한 문제점을 해결하기 위하여 UAV 자율비행기술을 미 공군 연구소와 미국 육군 공병대를 기반으로 정의하고 UAV 군집비행기술 및 보안위협을 분류하였다. 그리고 각 UAV 군집비행기술의 보안위협에 따른 보안요구사항을 정의하여 비교 분석함으로써 향후 안전한 UAC 자율비행 기술 발전에 기여할 수 있도록 하였다.

A Characteristic Analysis of Ergonomic Console Layout Studies Using Optimization Techniques

  • Jung, Kihyo;Kim, Jaejung;You, Taekho;Lee, Baekhee;Lee, Wonsup;Park, Seikwon;Roh, Woongseok;You, Heecheon
    • 대한인간공학회지
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    • 제31권6호
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    • pp.733-740
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    • 2012
  • Objective: The present study systematically analyzed the characteristics of ergonomic layout optimization methods by a comprehensive literature survey. Background: Although layout design methods for ergonomic placement of controls and displays on a console have been developed, understanding of their characteristics is lacking. Method: The present study analyzed layout optimization papers published past 20 years from the following four aspects: optimization model, optimization algorithm, design principle, and constraint/assumption. Results: The existing layout optimization methods based on various optimization techniques consider only a partial set of four layout principles(importance, frequency of use, sequence of use, and functional grouping) and two ergonomic criteria(visibility and reach). In addition, the existing methods oversimplify components in various sizes, shapes, and angles by assuming the equality of the components in size and shape. Conclusion: A more effective layout optimization method is needed which considers the layout principles and ergonomic criteria in a comprehensive manner and reflect the diversity of components in size and shape. Application: The identified characteristics on the existing layout optimization methods can be applicable to development of a better ergonomic console layout design method.

가상 환경 상의 헬리콥터 조종실 설계를 위한 정량적인 인간공학적 평가 방법 개발 (Development of Quantitative Ergonomic Assessment Method for Helicopter Cockpit Design in a Digital Environment)

  • 정기효;박장운;이원섭;강병길;엄주호;박세권;유희천
    • 대한인간공학회지
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    • 제29권2호
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    • pp.203-210
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    • 2010
  • For the development of a better product which fits to the target user population, physical workloads such as reach and visibility are evaluated using digital human simulation in the early stage of product development; however, ergonomic workload assessment mainly relies on visual observation of reach envelopes and view cones generated in a 3D graphic environment. The present study developed a quantitative assessment method of physical workload in a digital environment and applied to the evaluation of a Korean utility helicopter (KUH) cockpit design. The proposed assessment method quantified physical workloads for the target user population by applying a 3-step process and identified design features requiring improvement based on the quantified workload evaluation. The scores of physical workloads were quantified in terms of posture, reach, visibility, and clearance, and 5-point scales were defined for the evaluation measures by referring to existing studies. The postures of digital humanoids for a given task were estimated to have the minimal score of postural workload by finding all feasible postures that satisfy task constraints such as a contact between the tip of the index finger and a target point. The proposed assessment method was applied to evaluate the KUH cockpit design in the preliminary design stage and identified design features requiring improvement. The proposed assessment method can be utilized to ergonomic evaluation of product designs using digital human simulation.

Qualitative and quantitative analysis of furosine in fresh and processed ginsengs

  • Li, Yali;Liu, Xiaoxu;Meng, Lulu;Wang, Yingping
    • Journal of Ginseng Research
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    • 제42권1호
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    • pp.21-26
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    • 2018
  • Background: Furosine (${\varepsilon}$-N-2-furoylmethyl-L-lysine, FML) is an amino acid derivative, which is considered to be an important indicator of the extent of damage (deteriorating the quality of amino acid and proteins due to a blockage of lysine and a decrease in the digestibility of proteins) during the early stages of the Maillard reaction. In addition, FML has been proven to be harmful because it is closely related to a variety of diseases such as diabetes. The qualitative analysis of FML in fresh and processed ginsengs was confirmed using HPLC-MS. Methods: An ion-pair reversed-phase LC method was used for the quantitative analysis of FML in various ginseng samples. Results: The contents of FML in the ginseng samples were 3.35-42.28 g/kg protein. The lowest value was observed in the freshly collected ginseng samples, and the highest value was found in the black ginseng concentrate. Heat treatment and honey addition significantly increased the FML content from 3.35 g/kg protein to 42.28 g/kg protein. Conclusion: These results indicate that FML is a promising indicator to estimate the heat treatment degree and honey addition level during the manufacture of ginseng products. The FML content is also an important parameter to identity the quality of ginseng products. In addition, the generation and regulation of potentially harmful Maillard reaction products-FML in ginseng processing was also investigated, providing a solid theoretical foundation and valuable reference for safe ginseng processing.

4차 산업혁명을 위한 간호대학생의 글로벌 인재역량과 다중지능의 관계 (A Study of the Relation Between Nursing Students' Global Competences and Their Multiple Intelligences for the Fourth Industrial Revolution)

  • 오숙희;선정주;장성화
    • 융합정보논문지
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    • 제7권3호
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    • pp.13-26
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    • 2017
  • 본 연구는 4차 산업혁명을 위한 간호대학생의 글로벌 인재역량과 다중지능간의 관계를 알아보기 위한 서술적 상관관계 연구이다. 연구 대상은 전남과 전북에 소재한 4년제 간호학과 4개교에 재학중인 대학생 총 768명을 대상으로 편의 추출하였고, 총 768부중 733부가 분석되었다. 분석결과, 성별에 따른 글로벌 인재 역량과 학년에 따른 글로벌 인재역량은 유의한 차이가 있는 것으로 나타났으며, 남학생이 여학생보다 글로벌 인재역량이 훨씬 높은 것으로 조사되었다. 성별에 따른 다중지능과의 관계는 신체운동지능과 자기성찰지능에서 유의미한 차이가 있었고. 글로벌 인재역량이 다중지능에 유의미한 영향을 미치는 것으로 조사되었다. 따라서 본 연구결과는 간호교육과정 및 교육프로그램을 개발하는 데 기초자료 및 전략을 제공하는 데 일조할 것이다.