• Title/Summary/Keyword: Trend Curve

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FORECAST OF FASHION TO 1995 -Concerning the Behavioral Science Models of Fashion- (예측으로 본 1995년까지의 패션 경향 -패션의 행동 과학 모델을 중심으로-)

A Study on Reliability Growth through Failure Analysis by Operational Data of Avionic Equipments (항공전자장비의 운용자료 분석을 통한 신뢰성 성장 연구)

  • Jo, In-Tak;Lee, Sang-Cheon;Park, Jong Hun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.36 no.4
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    • pp.100-108
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    • 2013
  • In aerospace industry, MTBF (Mean Time Between Failure) and MFTBF (Mean Flight Time Between Failure) are generally used for reliability analysis. So far, especially to Korean military aircraft, MFTBF of avionic equipments is predicted by MIL-HDBK-217 and MIL-HDBK-338, however, the predicted MFTBF by military standard has a wide discrepancy to that of real-world operation, which leads to overstock and increase operation cost. This study analyzes operational data of avionic equipments. Operational MFTBF, which is calculated from operational data, is compared with predicted MFTBF calculated conventionally by military standard. In addition, failure rate trend is investigated to verify reliability growth in operational data, the investigation shows that failure rate curve from operational data has somewhat pattern with decreased failure rate and constant failure rate.

Bearing capacity of shallow footing under combined loading

  • Kusakabe, Osamu;Takeyama, Tomohide
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.3-25
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    • 2010
  • The paper deals with two bearing capacity problems of shallow footing under combined loading. The first is a FEM study of shallow strip footing on two-layer clay deposits subjected to a vertical, horizontal and moment combined loading, while the second is a centrifuge study of shallow rectangular footing on dry sand under double eccentricity. The FEM results revealed that the existence of top soft layer sensitively affects more on horizontal and moment capacity than vertical capacity for cases of footing on soft clay overlying stiff clay. Practical design charts are presented to evaluate bearing capacities of footing for various combinations of the ratio of the depth of the upper layer to the footing width and the ratio of undrained strength of the upper layer to that of the lower. The centrifuge tests indicated that current design practice of calculating failure load of rectangular surface footing under double eccentricity underestimates the centrifuge loading test data. This trend is more marked when the eccentricity becomes larger. The decreasing trend in failure load with an increase of double eccentricity is rather uniquely expressed by a single curve, using a newly defined resultant eccentricity and the diagonal length of the footing base.

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A Study on Design Characteristics of Domestic Furniture for Residence (국내 주거용 가구디자인 특성에 관한 연구)

  • Kim, Kook-Sun;Park, Sung-Won
    • Journal of the Korea Furniture Society
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    • v.16 no.2 s.30
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    • pp.49-57
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    • 2005
  • This study purposed to grasp the Design Characteristic of the representative Furnitures produced recently by Domestic Furniture Manufacturers. As for the researching method, setting as the object of the selected 7 furniture manufacturers, through the regional classification such as living room, bedroom, dining room, and then chose again the 395 items of furnitures to be analyzed. The Design Characteristic of the chosen furnitures has been examined clearly by the analysis standard framework for those peculiarities at view of aesthetic, decorating and material. As the result of analysis, as for the aesthetic Peculiarity of the furnitures, the rectilinear form was overwhelming than the curve lined shape, and it was appeared that the brighter tone of color was used quite more. In the respect of aesthetic characteristic, the furnitures decorated with modern style is pretty gaining predominance than that of reflected style of traditional character, and since modern residential space has been maintained continuously as minimal shaped trend for several years, it could be known that such moulding and decorating peculiarities and also furniture as the composing factor of space had been selected together with it. Based on such conclusion, standing on this time point where the design trend of residential space is being changed, it is also considered that the Development of Furniture Design which copes positively with such change tendency in the future.

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Influences and Barriers in the Kingdom of Saudi Arabia Affecting Technology Adoption in Healthcare: A Review Paper

  • Abdulaziz Alomari;Ben Soh
    • International Journal of Computer Science & Network Security
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    • v.23 no.6
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    • pp.59-67
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    • 2023
  • The healthcare industry continues to adopt and integrate smart technology in its operations, from medical devices to managing operations. However, the adoption curve has not been smooth, and the historical record of technology adoption in the Kingdom of Saudi Arabia reveals the existence of both known and unknown issues. This review paper is aimed to explain the influences and barriers present in the Saudi healthcare sector affecting IoT technology adoption. A comprehensive discussion of the literature illustrated that Vision 2030, the privatisation trend, transformation in disease patterns and ageing, issues in management and increasing public awareness are the key drivers that may influence the need for the medical Internet of Things (mIoT) in Saudi healthcare. However, based on the past trend, the introduction and adoption of mIoT will likely experience issues such as noncompliance from doctors and nurses due to negative beliefs, lack of knowledge and inadequate perception of effort requirements. Thus, in-depth research of the factors associated with mIoT technology adoption is suggested for a smooth transition.

Decision of G/R Ratio for the Correction of Mean-Field Bias of Radar Rainfall and Linear Regression Problem (레이더 강우의 평균보정을 위한 G/R 비의 결정과 선형 회귀 문제)

  • Yoo, Chulsang;Park, Cheolsoon;Yoon, Jungsoo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.5B
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    • pp.393-403
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    • 2011
  • This study theoretically reviewed the empirical G/R ratio by considering three regression and trend lines; the general linear regression curve, linear regression curve passing the origin, and the line passing the origin and the mass center of observed data. This review included the problem of choosing the independent variable and that of considering the zero measurements. This review result was also applied to the Typhoon Maemi in 2003 for their evaluation. Additionally, those regression and trend lines were compared using the RMSE between the corrected radar rainfall and observed rain gauge rainfall to select the most appropriate G/R ratio. Summarizing the results is as follows. First, the results of selecting the rain gauge rainfall as the independent variable were found better than the opposite case. Second, the effect of zero measurements varies depending on the structure of radar and rain gauge rainfall. Finally, the results from the comparison of three regression and trend lines shows that the slope of the regression line passing the origin with its independent variable of rain gauge rainfall would be used most appropriately for the G/R ratio, especially when the corrected radar rainfall is used for the flood analysis. The effect of zero measurements in this case was found not so significant.

Modeling of the Tensile Strength of Unsaturated Granular Soil Using Soil-water Characteristic Curve (흙-수분 특성 곡선을 이용한 불포화모래의 인장강도 모델링)

  • Kim Tae-Hyung;Kim Chan-Kee;Kim Tae-Hoon
    • Journal of the Korean Geotechnical Society
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    • v.20 no.7
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    • pp.171-181
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    • 2004
  • This study was conducted to explore the tensile strength models in granular soil at the full range of unsaturated state. Direct tension experiments were carried out with a newly developed direct tension technique. The measured experimental data were compared with theoretical models developed by Rumpf and Schubert for monosized ideal particulate solids at the unsaturated state. To do this, the soil-water characteristic curve obtained from a suction-saturation experiment was used to define the unsaturation state and the negative pore water pressure with different water content levels, which are important factors in theoretical tensile strength models. The nonlinear behavior of the tensile strength for unsaturated granular soil at the pendular state is appropriately simulated with Rumpf's model. For the funicular and capillary states, the predicted trend by Schubert's model is properly matched with the experimental data: tensile strength steadily increases and reaches a maximum value and then decreases until it reaches zero. This comparison supports the concept that the tensile strength of unsaturated real granular soil can be approximately simulated with theoretical models.

Effects of Pile Diameter on the Lateral Behavior of Offshore Pile in the Southwestern Area of Korea (서남해안 해상풍력단지 말뚝의 직경에 따른 횡방향 거동)

  • Lee, In;Choi, Younggyun;Kim, Honglak;Kwon, Osoon;Youn, Heejung
    • Journal of the Korean GEO-environmental Society
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    • v.14 no.5
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    • pp.23-32
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    • 2013
  • This paper presents the effect of pile diameter on the lateral behavior of offshore pile for wind turbine. The material parameters of the soils were estimated through SPT on the Southwestern offshore area in Korea, where the first wind farm is planned. The FDM software, FLAC3D, and LPile were adopted to derive the load-displacement curve, p-y curve, and maximum bending moment at a specified displacement. It was found that the results from softwares significantly differ and the LPile could overestimate the allowable capacity. The maximum bending moment along the pile with 2m diameter could be as large as four times the bending moment with 1m diameter. Similar trend was observed for the allowable lateral capacity.

ENVIRONMENTAL DEPENDENCE OF TYPE IA SUPERNOVA LUMINOSITIES FROM THE YONSEI SUPERNOVA CATALOG

  • Kim, Young-Lo;Kang, Yijung;Lee, Young-Wook
    • Journal of The Korean Astronomical Society
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    • v.52 no.5
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    • pp.181-205
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    • 2019
  • There is evidence that the luminosities of Type Ia supernova (SN Ia) depend on their environments. While the impact of this trend on estimating cosmological parameters is widely acknowledged, the origin of this correlation is still under debate. In order to explore this problem, we first construct the YONSEI (YOnsei Nearby Supernova Evolution Investigation) SN catalog. The catalog consists of 1231 spectroscopically confirmed SNe Ia over a wide redshift range (0.01 < z < 1.37) from various SN surveys and includes light-curve fit data from two independent light-curve fitters, SALT2 and MLCS2k2. For a sample of 674 host galaxies, we use the stellar mass and the star formation rate data in Kim et al. (2018). We find that SNe Ia in low-mass and star-forming host galaxies are $0.062{\pm}0.009mag$ and $0.057{\pm}0.010mag$ fainter than those in high-mass and passive hosts, after light-curve corrections with SALT2 and MLCS2k2, respectively. When only local environments of SNe Ia (e.g., locally star-forming and locally passive) are considered, this luminosity difference increases to $0.081{\pm}0.018mag$ for SALT2 and $0.072{\pm}0.018mag$ for MLCS2k2. Considering the significant difference in the mean stellar population age between the two environments, this result suggests that the luminosity evolution of SNe Ia with redshift is most likely the origin of the environmental dependence.

On the Global and Local Environmental Dependence of Type Ia Supernova Luminosity from the Analysis of SALT2 and MLCS2k2 Light-Curve Fitters

  • Kim, Young-Lo;Lee, Young-Wook
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.40.3-40.3
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    • 2019
  • There is growing evidence for the dependence of Type Ia supernova (SN Ia) luminosities on the environments. The origin of this correlation, however, is under debate. In order to explore the physical origin of the trend in detail, we analyze SN Ia light-curves by combining a sample of 1231 SNe Ia over a wide redshift range (0.01 < z < 1.37) in various SN surveys and employing two independent light-curve fitters of SALT2 and MLCS2k2. Although SALT2 is the most widely used fitter in the SN community, MLCS2k2 has a novelty in the context of an investigation of the luminosity evolution of SNe Ia. For this reason we use both fitters and analyze them separately. We also determine a stellar mass and a star formation rate (SFR) for a sample of ~600 host galaxies. In addition, because recent low-redshift studies suggest that this dependence manifests itself most strongly when using the local SFR at the SN location, we introduce a new method to infer the local environments by restricting the SN Ia sample in globally star-forming host galaxies to a low-mass host galaxy subset (${\leq}10^{10}M_{\odot}$). We find that SNe Ia in low-mass and star-forming host galaxies are fainter than those in high-mass and passive hosts, after light-curve corrections. Especially, for the first time in host studies, we show that SNe Ia in locally star-forming environments are $0.081{\pm}0.018$ mag fainter ($4.5{\sigma}$) than those in locally passive environments from the sample including SNe at the high-redshift range. Considering the significant difference in the mean stellar population age between these environments, the result would suggest that the origin of the environmental dependence is the luminosity evolution of SNe Ia.

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