• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.641-644
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• 2006

Considering properties of the low-heat concrete mixed with the blended cements, the influences compared blended cements with ordinary portland cement made experiments on. (1) Blended cements were superior to OPC in the fresh concrete flow that the use of blended cements reduced chemical admixture. (2) The more the use of additive increase, the more bleeding happens. So it is considered to heights, order, and rate of placement, curing methods and so on. (3) The use of blended cements increase long term strength after 28 days, but decrease early strength and durability. So it is considered to the curing methods and early frost damage, and endurance limit.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권5호
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• pp.546-553
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• 2015

Recently, flash cache is widely adopted as the performance accelerator of legacy storage systems. Unlike other cache media, flash cache should be carefully managed as it has peculiar characteristics such as long write latency and limited P/E cycles. In particular, we make two prominent observations that can be utilized in managing flash cache. First, a serious worn-out problem happens when the working-set of a system is beyond the capacity of flash cache due to excessively frequent cache replacement. Second, more than 50% of data has no hit in flash cache as it is a second level cache. Based on these observations, we propose a cache admission control policy that does not cache data when it is first accessed, and inserts it into the cache only after its second access occurs within a certain time window. This allows the filtering of data disruptive to flash cache in terms of endurance and performance. With this policy, we prolong the lifetime of flash cache 2.3 times without any performance degradations.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 추계 학술대회논문집
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• pp.165-171
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• 2004

Smart UAV, which adopting tiltrotor aircraft concept, requires long endurance and high speed capability simultaneously These two contradictable flight performances are hard to meet with single wing concept and inevitably require the operation of flap system which should reveal optimal performance for each flight mode. In order to design SUAV flaperon satisfying the performance requirement, various configurations are generated and their aerodynamic performances are analyzed using numerical flow computations around flaps. Considering aerodynamic performance and manufacturing simplicity, a final flap configuration is selected.

• International Journal of Aeronautical and Space Sciences
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• 제7권1호
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• pp.99-105
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• 2006

In this study, nonlinear static and dynamic aeroelastic analyses for a high-aspect-ratio wing have been performed. To achieve these aims, the transonic small disturbance (TSD) theory for the aerodynamic analysis and the large deflection beam theory considering a geometrical nonlinearity for the structural analysis are applied, respectively. For the coupling between fluid and structure, the transformation of a displacement from the structural mesh to the aerodynamic grid is performed by a shape function which is used for the finite element and the inverse transformation of force by work equivalent load method. To validate the current method, the present analysis results of a high-aspect-ratio wing are compared with the experimental results. Static deformations in the vertical and torsional directions caused by an angle of attack and gravity loading are compared with experimental results. Also, static and dynamic aeroelastic characteristics are investigated. The comparisons of the flutter speed and frequency between a linear and nonlinear analysis are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.461-464
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• 1988

In order to use mBIZ code as the practical transmission code, the information block length have to be determined. If the information block length is short, timing information disapperance is reduced, but transmission speed is increased as the result of inserted redundancy bit. While, if the information block length is long, timing information disapperance and jitter are caused. So it is very important to determine the optimal timing information block length. Therefore, in this paper, we determined the optimal information block length using S/X endurance method.

• 항공우주기술
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• 제1권2호
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• pp.179-185
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• 2002

본 연구는 장기체공성 향상을 위한 개량형 무인기의 구조설계에 관한 방법 및 절차를 소개한 것이다. 상온 경화용 복합재료를 날개 전체에 적용하였다. 운반 및 보관의 용이성을 고려하여 날개 구조물을 3개로 분리하였고, 구조물의 경량화 및 강성의 증가를 위하여 샌드위치 구조물을 스킨 전영역에 적용하였고, 제한하중 4g에 해당되는 하중조건에서 구조강도시험을 수행하여 구조설계와 제작성을 점검하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.684-689
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• 2002

This paper represents the life-cycle cost(LCC) of steel bridges which are located on the train-network. Corrosion problems are mainly considered in the steel members such as steel plate girder, box girder, truss and arch. Based on the current value, initial construction cost, maintenance cost and demolition cost are calculated and life-cycle costs are formulated for the several types of bridges. From the comparison on each LCC, an effective painting method is recommended for reducing the LCC of steel bridges. Even though the initial cost of Super Weather Resistance Heavy Duty Paintings (Resin Fluoride) is expensive, because of the long endurance, the LCC of steel bridges painted with Super Weather Resistance Heavy Duty Paintings (Resin Fluoride) is less than that painted with General Heavy Duty (Rubber Chloride).

• 한국군사과학기술학회지
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• 제15권4호
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• pp.410-416
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• 2012

In recent years, unmanned underwater vehicles(UUVs) have emerged as viable technical solution for conducting underwater search, surveillance, and clearance operations in support of mine countermeasure missions(MCMs) because of her autonomy and long time endurance capability. It is necessary for UUV for MCM system design to define system specification from various configuration alternatives. This paper introduces a simulation model for mine countermeasure mission effectiveness analysis and presents some simulation results under various tide conditions for validation of the proposed simulation model.

• 한국항공운항학회지
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• 제27권1호
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• pp.51-56
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• 2019

To reduce the structural weight, thin-walled circular composite tube has been used as a main spar of high altitude-long endurance unmanned air vehicle(HALE UAV). Predicting the torsional response of stiffened circular spar is complex due to the inhomogeneous nature of section properties, which are dependent on fiber architecture and constituent material properties. The stiffener were placed in the top and bottom sectors of a tube to increase the torsional capabilities such as the rigidity and buckling strength. Numerical simulations were performed to estimate the effect of the stiffener on the torsional capacities. A static experimental test was performed on a stiffened tube, and the test results were compared with a numerical model. The numerical models showed good correlation and demonstrated the ability to predict the torsional capacity. Results presented herein will exhibit the effectiveness of stiffener on torsional strength and stiffness.

• 대한간호학회지
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• 제26권4호
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• pp.833-852
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• 1996

Regular long term dance movement could be one of ways to induce improvement of psychophysiological variables, resulting in improvement of quality of life. However, there have been few studies to evaluate the effect of dance movement training on both physiological and psychological variables in the elderly. This study was focused to determine the effect of Korean traditional dance movement training on psychophysiological variables-body weight, body fat, lean body mass, muscle strength, muscle endurance, flexibility, agility, resting heart rate and blood pressure, depression and life satisfaction-in Korean elderly women. Thirty four subjects, aged between 65 and 75years who have normal cognition, sensory function, cerebellum function, cardiovascular function, participated in this study. Seventeen experimental group subjects were selected from E-elderly university in Kyung Gi province, and Seventeen control group subjects were selected from N-welfare facility in Seoul City. Seventeen experimental group subjects participated for 12weeks dance movement program. Korean traditional dance movement program was developed on the basis of Korean traditional dance and music by the author. The program consisted of approximately 50minutes of dance, 3times a week for 12weeks. During 50minutes workout, there were 15minutes of warm-up dancing, 25minutes of conditioning dance and 10minutes of cool-down dancing. The intensity for the conditioning phase was at between 60% and 65% of age-adjusted maximum heart rates. The body weight, body fat, lean body mass, muscle strength(grip strength, leg strength), muscle endurance, flexibility, agility, resting heart rate and blood pressure, depression and life satis-faction were measured prior to and following the experimental treatment. The participants in dance movement were interviewed focusing on subjective feeling following 12 week's regular dance movement. Data were analyzed with mean, standard deviation, percentage of change, X²-test, t-test, and ANCOVA test using SPSS PC/sup +/ program. Subjective feeling was categorized into cognitopsy-chological and physiological responses. Results were obtained as follows : 1) The body weight (F=15.52, p=.000), body fat (F=18.33, p=.000) and lean body mass (F=7.28, p=.011) of the experimental group were significantly lower than those of the control group following the dance movement training. 2) The leg strength (F=30.96, p=.000), muscle endurance (F=9.06, p=.005), agility(F=44.92, 000), flexibility(F=6.84, p=.014) of the experimental group were significantly higher than those of the control group following the dance movement training. There was no significant difference of grip strength(F=.43, p=.515) between experimental and control groups. 3) The heart rate(F=26.96, p=.000), systolic (F=10.40, p=.000) and diastolic(F=3.99, p=.005) blood pressure at rest of the experimental group were significantly lower than those of the control group following the dance movement training. 4) No significant difference of score of depression (F=3.49, p=.071) was observed between experimental and control groups. 5) Score of life satisfaction of experimental group was remarkably higher than that of control group following 12weeks of dance movement training (p<0.05). 6) Thematic responses about the dance movement following the training were positive. "I feel good" was the most frequent among cognitopsychological responses and "I feel lightness of body" was the most frequent among physiological responses. The results suggest that Korean traditional dance movement training can improve psychophysiological variables of Korean elderly.