• Title/Summary/Keyword: T-test analysis

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Analysis of Skin Friction Behavior in Prebored and Precast Piles Based on Field Loading Test (재하시험을 통한 매입말뚝의 주면마찰력 거동 분석)

  • Jung, Gyoung-Ja;Kim, Do-Hyun;Lee, Chul-Ju;Jeong, Sang-Seom
    • Journal of the Korean Geotechnical Society
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    • v.33 no.1
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    • pp.31-38
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    • 2017
  • Skin friction of prebored and precast pile may be one of the most critical factors affecting the bearing capacity and settlement. Special attention was given to the interface behavior of pile-cement milk-surrounding soil when the load is acting on the prebored and precast pile. The cases of single pile were analyzed through a three-dimensional finite element approach and pile loading tests. A series of numerical analyses of the interface of pile-cement milk-soil was conducted with the proposed t-z curve and field measurements. It is shown that the use of cement milk around the pile increases the skin friction and reduces the pile settlement. It is also known that the suggested t-z curve between the cement milk and the soil, enhances the accuracy of the numerical analysis results.

Effects of forestry host plants, rearing seasons and their interaction on cocoon productivity of tropical tasar silkworm, Antheraea mylitta in uttarakhand

  • Bhatia, N.K.;Yousuf, Mohd.
    • International Journal of Industrial Entomology and Biomaterials
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    • v.30 no.2
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    • pp.31-39
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    • 2015
  • Antheraea mylitta Drury (Lepidoptera: Saturniidae) is a commercial silk producing forest insect of India, but it has never been experimented in Uttarakhand state in spite of the huge availability of its forestry host plants. This is the first study on A. mylitta in Uttarakhand. The goal of this study is to introduce forest based commercial rearing of A. mylitta, in tropical forest areas of Uttarakhand to reduce poverty among forest dependent people. In current study, we assessed the effect of seven forest tree species, rearing seasons, and their interactions on cocoon productivity of Daba (bivoltine) ecorace of A. mylitta in the New Forest of FRI, Dehra Dun during 2012 and 2013 and collected the data that was analysed by two-way completely randomized block factorial design. Post HOC Tukey's HSD test was carried out to compare the homogeneous pairs of means. We also carried out Evaluation Index analysis to rank the tested forestry host plants for better growth and development of A. mylitta under the climatic condition of Uttarakhand. Analysis of variance indicated that cocoon yield of A. mylitta differed significantly between rearing seasons (DF=1, F=88.24, p<0.05) and host plants (DF 6, F= 368.63, p<0.05); however, their interactions were found insignificant (DF=6, F=0.99, p>0.05). In first rearing season of July-August, there was higher cocoon yield than the second season of September-November. Results indicated that Terminalia alata fed larvae showed significantly higher cocoon yield (164.11 cocoons/300 larvae); followed by, T. tomentosa (148.89 cocoons), T. arjuna (140.00 cocoons) and Lagerstroemia speciosa (129.47 cocoons) fed larvae. Whereas, Lagerstroemia tomentosa fed larvae that was used by the first time in India, showed lowest cocoon yield (48.81 cocoons), followed by T. chebula (72.53 cocoons) fed larvae. Cocoon yield of T. tomentosa and T. arjuna fed larvae of A. mylitta did not differ significantly with each other.

Risk of Fracture Prevalence and Glycemic Control in Korean Older and Middle-aged Patients with Diabetes: A Retrospective Analysis of a Cohort Derived from the Korean National Health Insurance Sharing Service Database, 2009-2013 (노인과 중년 당뇨병 환자의 골절의 발생 빈도 위험과 혈당조절의 관계)

  • Sin, Hye Yeon
    • Korean Journal of Clinical Pharmacy
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    • v.28 no.3
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    • pp.194-203
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    • 2018
  • Background: Bone fractures are high in elderly patients with type 2 diabetes mellitus (T2DM). Hyperglycemia and chronic kidney disease may increase the risk of fracture prevalence via altered bone metabolism, but whether glycemic control and kidney function are associated with the risk of fracture prevalence remains unclear. This study evaluated the relationship between glycemic control and baseline estimated glomerular filtration rate (eGFR) and risk of fracture prevalence in older and middle-aged patients with T2DM. Methods: Patients who underwent a general medical check-up between 2009 and 2013 were selected from the Korean National Health Insurance Sharing Service records. Chi-square test and multiple logistic regression analysis were used to assess the relationship between glycemic control and eGFR and risk of fracture prevalence. Results: Cumulative fracture prevalence were higher in patients with T2DM, irrespective of whether they had tight or less stringent glycemic control (fasting blood glucose [FBG] ${\geq}110mg/dL$). After adjustment for baseline age and FBG, tight and less stringent glycemic control was significantly associated with increased adjusted risk of fracture prevalence in middle-aged patients with T2DM (OR=1.13, 95% CI, 1.05-1.21, p=0.0005 vs OR=1.13, 95% CI, 1.06-1.20, p=0.0001), but not in older patients. Baseline eGFR was not significantly related to fracture prevalence in either older or middle-aged patients. Conclusion: Less stringent glycemic control significantly increased the adjusted risk of fracture prevalence in middle-aged patients with T2DM. Further studies are needed to confirm the effect of tight glycemic control on fracture prevalence.

Comparison of Self-Esteem and Quality of Life in Patients on Hemodialysis and Peritoneal Dialysis (혈액투석환자와 복막투석환자의 자아존중감과 삶의 질 비교)

  • Chun, Chung Ja;Jung, Young Mi
    • Korean Journal of Adult Nursing
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    • v.12 no.4
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    • pp.706-716
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    • 2000
  • The purpose of this study was to provide fundamental data for nursing intervention by assessing self-esteem and quality of life(QL) in patients on hemodialysis and peritoneal dialysis. The subjects of this study were 60 patients on hemodialysis at H university medical center in Seoul and 56 patients on peritoneal dialysis at B company. The analysis was done by using t-test, ANOVA, Scheffe and Stepwise multiple regression. The results were as follows: 1. The average self-esteem score was significantly higher in patients on hemodialysis (27.98) than in patients on peritoneal dialysis (25.64). And there were no statistically significant differences between patients on hemodialysis(128.45) and patients on peritoneal dialysis(122.83) in the scores on QL. Among four factors of QL, hemodiaysis patients showed higher score than peritoneal dialysis patients in all factors. But, only family had statiscally significant differences. Also family showed the highest score in both groups, but psychomental showed the lowest score. 2. In patients on hemodialysis, self-esteem was significantly different by occupation(t=3.122, p=.003) and in patients on peritoneal dialysis by age(F=4.450, p=.007), education level(F=7.458, p=.001) and occupation (t=2.491, p=.017). Also in patients on hemodialysis, QL was significantly different by occupation(t=2.223, p=.033) and in patients on peritoneal dialysis by education level(F=4.007, p=.024), and occupation (t=2.806, p=.007). 3. Self-esteem accounted for 36.3% of variance in QL and monthly income accounted for an additional 6.1% of QL in hemodialysis patients by means of stepwise multiple regression analysis. In peritoneal patients, self-esteem accounted for 65.1% and monthly income accounted for an additional 2.7% in QL.

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Analysis of Immune Responses Against Nucleocapsid Protein of the Hantaan Virus Elicited by Virus Infection or DNA Vaccination

  • Woo Gyu-Jin;Chun Eun-Young;Kim Keun Hee;Kim Wankee
    • Journal of Microbiology
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    • v.43 no.6
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    • pp.537-545
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    • 2005
  • Even though neutralizing antibodies against the Hantaan virus (HTNV) has been proven to be critical against viral infections, the cellular immune responses to HTNV are also assumed to be important for viral clearance. In this report, we have examined the cellular and humoral immune responses against the HTNV nucleocapsid protein (NP) elicited by virus infection or DNA vaccination. To examine the cellular immune response against HTNV NP, we used $H-2K^b$ restricted T-cell epitopes of NP. The NP-specific $CD8^+$ T cell response was analyzed using a $^{51}Cr-release$ assay, intracellular cytokine staining assay, enzyme-linked immunospot assay and tetramer binding assay in C57BL/6 mice infected with HTNV. Using these methods, we found that HTNV infection elicited a strong NP-specific $CD8^+$ T cell response at eight days after infection. We also found that several different methods to check the NP-specific $CD8^+$ T cell response showed a very high correlation among analysis. In the case of DNA vaccination by plasmid encoding nucleocapsid gene, the NP-specific antibody response was elicited $2\~4$ weeks after immunization and maximized at $6\~8$ weeks. NP-specific $CD8^+$ T cell response reached its peak 3 weeks after immunization. In a challenge test with the recombinant vaccinia virus expressing NP (rVV-HTNV-N), the rVV-HTNV-N titers in DNA vaccinated mice were decreased about 100-fold compared to the negative control mice.

Mediating effect of communication ability in the relation between empathy and interpersonal relation in nursing students (간호대학생의 의사소통 능력과 대인관계에서 공감의 매개효과)

  • Jo, Eunhee;Kim, Hyun-Sook;Hwang, Soon-Jung
    • The Journal of Korean Academic Society of Nursing Education
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    • v.26 no.3
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    • pp.290-298
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    • 2020
  • Purpose: This study aimed to grasp the correlation between communication ability, empathy, and interpersonal relations among nursing students, and to explore the mediating effect of empathy on the relation between communication and interpersonal relation in nursing students. Methods: Participants were 209 college students in the Department of Nursing at two universities. The data collection period was from October 1, 2019 to November 1, 2019. The questionnaire consisted of measuring tools for general characteristics, communication ability, interpersonal relation and empathy. SPSS/23.0 program was used. The analysis used descriptive statistics, Pearson's correlation coefficient, independent t-test, one-way ANOVA, multiple regression analysis, and Sobel's tests. Results: The communication ability was nursing major satisfaction (t=8.25, p<.001), and last year's average grade (t=7.29, p=.001). Interpersonal relationships showed significant differences in gender (t=2.51, p=.013) and nursing major satisfaction (t=10.99, p<.001). Communication ability and empathy (r=.37, p<.001), communication ability and interpersonal relation (r=.77, p<.001), empathy and interpersonal relation (r=.43, p<.001) showed a significant static correlation. In communication ability and interpersonal relation, empathy had a partial mediating effect (Z=2.97, p<.001), and explanatory power was 62%. Conclusion: To improve the communication ability and interpersonal relation of nursing students, it is necessary to develop a personalized and empathy-enhanced education program for each grade.

Study of IoT Module Package Design Optimization for Drop Testing by Drone (IoT 모듈 패키지 디자인 최적화 및 드론에서의 낙하해석 연구)

  • Jo, Eunsol;Kim, Gu-Sung
    • Journal of the Microelectronics and Packaging Society
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    • v.28 no.4
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    • pp.63-67
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    • 2021
  • In order to detect fires that may not be visible to the naked eye, an IoT module that uses changes in Carbon dioxide (CO2) levels and temperature to effectively identify ambers (dying flames) was developed. Finite element analysis was then used to optimize the packaging for this module. Given the nature of ambers, the low power long range LoRa (Long Range) technology was used in the development of this module. To protect the module, a number of packages were designed, and comparative analysis performed on the stress generated when they fall. The results of which show that Model C showed the lowest stress. In addition, unlike other models in which stress concentration was predicted in the module mounting part of the package, in this model the stress concentration phenomenon was predicted in the wing part. It was therefore determined that this approach is ideal for protecting the internal module, and a package to which this was applied was manufactured.

The Study on Dynamic Analysis of Durability of a Wheel using CAE (CAE를 이용한 휠 내구성능 동역학 해석을 위한 연구)

  • Park, Jae Heung;Park, Tae Won;Jung, Sung Pil
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.12
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    • pp.1296-1303
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    • 2012
  • There is a certain limit to reproduce phenomena between the real vehicle and road, since the existing methods to verify durability of the wheel are mostly uni-axial tests. And the change of durability of the wheel can't be predicted since these tests don't consider the camber angle and lateral force as important factors. In this paper, the FE models of the wheel-tire and drum are created. Then, the vertical and lateral loads are applied to wheel-tire assembly and the camber angle is applied by inclining the wheel-tire assembly to the drum. Based on the analysis result, the crack position is predicted to be created in the body of the wheel. The variation of the stress according to the camber angle is verified and the maximum spot of the stress changes continually.

Measurement Conditions of Concrete Pull-off Test in Field from Finite Element Analysis (유한요소 해석을 이용한 현장 콘크리트 부착강도 측정조건)

  • Kim, Seong-Hwan;Jeong, Won-Kyong;Kwon, Hyuck;Kim, Hyoun-Oh;Lee, Bong-Hak
    • Journal of Industrial Technology
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    • v.22 no.A
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    • pp.185-192
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    • 2002
  • The performance of old and the new concrete construction depends upon bond strength between old and the new concrete. Current adhesive and strength measurement method ignores the effect of stress concentration from shape of specimens. Therefore, this research calculates stress concentration coefficient as the ratio of drilling depth to drilling diameter($h_s/D$), the ratio of overlay thickness to drilling diameter($h_0/D$), the ratio of steel disk thickness to drilling diameter(t/D), the ratio of overlay elastic modulus to substrate modulus($E_1/E_0$), the distance from core to corner border(L_$_{corner}$) and the distance between cores(L_$_{coic}$) vary. The finite element method is adapted to analysis The results from 'the F.E.M analysis are as follows. The stress concentration effects can be minimized when the ratio of drilling depth to drilling diameter($h_s/D$) is 0.20~0.25, the elastic modulus ratio($E_1/E_0$) is 06~1.0, and the ratio of steel disk thickness to drilling diameter(t/D) is 3.0. The overlay thickness, the distance from specimens to corner border(L_$_{corner}$), the distance between cores(L_$_{coic}$) almost do not affect to the stress concentration.

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Dynamic model updating of the laminated composite plate using natural frequencies measured from modal test (고유진동수의 실험값을 사용한 복합재 적층판의 동적 모델링 개선)

  • 홍단비;유정규;박성호;김승조
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.340-346
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    • 1998
  • In order to improve the prediction of dynamic behavior in structures, several lower vibration modes from FFT analysis through experiments are used to update the mechanical properties followed by the updated frequencies from numerical analysis. Performance index consists of the sum of error norms between the chosen frequencies and corresponding frequencies from numerical analysis. As an updating process of the natural frequencies, the optimization algorithm based on conjugate gradient method is adopted. The gradient of performance index is calculated using the sensitivity of selected eigenvalues with respect to each design parameter. The mechanical properties of lamina, E$\_$l/, E$\_$2/, .nu.$\_$12/ and G$\_$12/, are design parameters for the updating process. The proposed method is applied to predict the dynamic behavior of composite laminated plates of [0]$\_$8T/ and [.+-.45]$\_$2S/ separately or interchangeably. Also, the mixed case for [0]$\_$8T/ and [.+-.45]$\_$2S/ is exarm'ned to check the possibility for the improved prediction generally. The good agreement is obtained between the measured frequencies and the numerical ones. Based on the results for all the cases studied, the proposed approach has a clear potential in characterizing the mechanical properties of composite lamina.

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