• Title/Summary/Keyword: Student-t분포

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Factors Influencing Type D Personality of Female Undergraduate Students Majoring in Nursing (간호학전공 여대생의 D유형 성격에 영향을 미치는 요인)

  • Noh, Jun Hee;Lim, Eun Ju;Jeong, Yong-Sun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.12
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    • pp.6265-6274
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    • 2013
  • The aim of this study was to clarify the variables influencing the Type D personality of female university students majoring in nursing. The subjects were 353 female students attending a nursing college, and multiple regression analysis was performed using the PASW 18.0 program. The distribution of Type D personality in the subjects was 34.8%. The factors influencing the Type D personality included the support of family and friends, satisfaction with their major, self-esteem, life stress, and resilience. The factor with the greatest influence among the variables was life stress, and the explanatory power of this model was 36.3%. Intervention programs should be developed to reduce the level of Type D personality among nursing college students to provide them with the appropriate expertise as prospective nurses.

THE RELIABILITY OF LASER DOPPLER FLOWMETER IN PULP VITALITY TEST OF TEETH (치수생활력 검사 방법으로서 laser Doppler flowmeter의 신뢰도)

  • Nam, Dong-Woo;Kim, Young-Jin;Nam, Soon-Hyeun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.25 no.4
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    • pp.683-690
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    • 1998
  • The purpose of this study was to evaluate the reliablity of laser Doppler flowmeter on the permanent maxillary central incisors with open apex. Laser Doppler flowmeter and electric pulp tests were done in 35 elementary students aged between 8 and 9 years and 35 females and males aged between 23 and 24 years. Teeth with open apex were confined to root developmental stage 5 and 6 by Moorrees classification. The threshold of electric pulp tests was decided the time of tingling sensation. More than three different electric pulp tests applied on every teeth with more than 3 minutes interval between each teeth due to the false response. Laser Doppler flowmeter test stablilzation and observation stages took more than 5 minutes each LDF values and electric pulp test thresholds were analyzed with student t-test. The results were as follows: 1. The electric pulp test threshold on teeth with immature and mature roots showed 28.4% and 100% response respectively, and the the LDF values on teeth with immature and mature roots showed 100% response. 2. The EPT thresholds on teeth with immature roots were larger than thresholds on teeth with mature roots(p<0.01). 3. No significant differences were found in the LDF values on teeth with immature and mature roots.

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An Empirical Study on the Characteristics of Stock Returns in Chinese Stock Market -Focusing on the period of 1995 to 2007 - (중국 주식시장의 수익률 특성에 관한 실증연구 - 1995년부터 2007년 기간을 중심으로 -)

  • Kim, Kyung Won;Choi, Joon Hwan
    • International Area Studies Review
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    • v.13 no.3
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    • pp.287-308
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    • 2009
  • This article examines the distributional characteristics of the return of Chinese stock market indices. The majority of previous empirical researches have tended to focus upon the simple stock market index. However, this study focuses on the four indices which represent the characteristics of each stock market index. The empirical findings indicate that the returns of the four chinese indices are not normally distributed at conventional levels. The Ljimg-Box -statistics indicate the returns of the index of A shares are not serially autocorrelated. However, the returns of the index of B shares are serially autocorrelated. The empirical findings also indicate returns of the four chinese indices are not serially autocorrelated. The statistics of Regression Specification Error Test and ARCH indicate the returns of all four indices are not serially linear. The findings also indicate that E- GARCH model is the most fittest model for the returns of the four chinese indices and the forecast error can be reduced by using student t distribution rather normal distribution.

The influence of adjacent tooth to the microbiology of implant sulcus (인접치아가 임플란트 치은연하 세균총의 분포에 미치는 영향)

  • Lee, Dong-Young;Lee, Man-Sub;Kwon, Young-Hyuk;Park, Joon-Bong;Herr, Yeek;Chung, Jong-Hyuk
    • Journal of Periodontal and Implant Science
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    • v.35 no.3
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    • pp.563-575
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    • 2005
  • The aim of present study is to evaluate the influence of adjacent tooth to the microbiology of clinically healthy implant. Control group included patients who had clinically healthy implant and tooth with healthy $periodontium(PD{\leq}3mm)$, test group was composed of patients who had clinically healthy implant and tooth with periodontal pocket(PD>3mm). The criteria of clinically health implant are no pain or discomfort, the restorative suprastructure provide satisfactory fit and function, and the tissue around the fixtures were firm and probing with standard periodontal probe with a rounded tip 0.5mm in diameter resulted in penetration of no more than 5mm when using a force of 0.5N at any location. 38 patients, partially edentulous subjects with endosseous root-form implants were selected. All subjects were medically healthy and had not taken systemic antibiotics and professional plaque control 3 months before sampling. Number of control group is 25(mean age $52{\pm}13$, 26 teeth, 34 implants) and test group is 13(mean age $60{\pm}13$, 13 teeth, 17 implants). All teeth and implants of each patient were examined probing depth(PD), bleeding on probing(BOP), and plaque index(PI), and samples of subgingival plaque were obtained at each site with sterile curet or fine paper points, then the plaque transferred to PBS. Obtained samples were examined for the presence of P. gingivalis, T. forsythensis, and T. denticola by the polymerase chain reaction(PCR). The relationship among clinical parameters and the colonizations by the 3 bacterial species from natural teeth and implants region were analyzed by student t-test. The results of this study were as follows: 1. PD was different in teeth between 2 groups(p<0.05), but the other parameters were not. 2. Statistically significant difference was not found in clinical parameters of implants between 2 groups. 3. All bacterial prevalences of teeth were higher in test group than in control group, and prevalence of T. forsythensis had statistically significant difference between 2 groups(p<0.05). 4. Prevalences of P. gingivalis and T. forsythensis are higher in test group than control group, and that of T. denticola is higher in control group than in test group. But there were no statistically significant differences between 2 groups. In conclusion, there is no statistically significant difference in prevalence of implant microbiology between 2 groups. But if the number of samples increased, it will be possible to find out statistical significance in prevalence of P. gingivalis. It seems that pocket of adjacent tooth influences prevalence of P. gingivalis. These results mean that improvement of the periodontal condition before implantation is very important.

Study on Levels of Mathematically Gifted Students' Understanding of Statistical Samples through Comparison with Non-Gifted Students (일반학급 학생들과의 비교를 통한 수학영재학급 학생들의 표본 개념 이해 수준 연구)

  • Ko, Eun-Sung;Lee, Kyeong-Hwa
    • Journal of Gifted/Talented Education
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    • v.21 no.2
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    • pp.287-307
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    • 2011
  • The purpose of this study is to investigate levels of mathematically gifted students' understanding of statistical samples through comparison with non-gifted students. For this purpose, rubric for understanding of samples was developed based on the students' responses to tasks: no recognition of a part of population (level 0), consideration of samples as subsets of population (level 1), consideration of samples as a quasi-proportional, small-scale version of population (level 2), recognition of the importance of unbiased samples (level 3), and recognition of the effect of random sampling (level 4). Based on the rubric, levels of each student's understanding of samples were identified. t tests were conducted to test for statistically significant differences between mathematically gifted students and non-gifted students. For both of elementary and middle school graders, the t tests show that there is a statistically significant difference between mathematically gifted students and non-gifted students. Table of frequencies of each level, however, shows that levels of mathematically gifted students' understanding of samples were not distributed at the high levels but were overlapped with levels of non-gifted students' understanding of samples.

Basic Study of Spray-Behavior Characteristics of Emulsified Fuel (에멀젼연료의 분무거동특성에 관한 기초연구)

  • Yeom, Jeong Kuk;Yoon, Jeong Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.38 no.9
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    • pp.763-771
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    • 2014
  • As a preliminary study on the spray behavior characteristics of emulsified fuel, the fuel properties (viscosity, surface tension, and density) and evaporation characteristics of a fuel droplet were investigated. The emulsified fuel was made by mixing diesel and $H_2O_2$. In addition, the macroscopic spray behavior characteristics such as the spray penetrations and spray angles of the emulsified and diesel fuels were compared. The stirring condition of the emulsified fuel was a 9:1 mixture of the diesel fuel and the surfactant span 80. The mixing ratios for the hydrogen peroxide were set at EF2, EF12, EF22, EF32, EF42, EF52, EF62, EF72, EF82, and EF92. The injection pressures were set at 400, 600, 800, and 1000 bar. We found that as the mixing ratio of the hydrogen peroxide was increased from EF2 to EF52, the viscosity of the emulsified fuel increased. However, afterward, the viscosity of the emulsified fuel gradually decreased and approached the viscosity value of the diesel fuel. Therefore, generally oil-in-water emulsions were used for the hydrogen peroxide mixing ratios up to 52 (EF52), and water-in-oil emulsions were used for the hydrogen peroxide mixing ratios above 52. Finally, the spray behavior characteristics (spray penetration and spray angle) of the emulsified fuel were found to be almost independent of the mixing ratio.

Probabilistic Medium- and Long-Term Reservoir Inflow Forecasts (II) Use of GDAPS for Ensemble Reservoir Inflow Forecasts (확률론적 중장기 댐 유입량 예측 (II) 앙상블 댐 유입량 예측을 위한 GDAPS 활용)

  • Kim, Jin-Hoon;Bae, Deg-Hyo
    • Journal of Korea Water Resources Association
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    • v.39 no.3 s.164
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    • pp.275-288
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    • 2006
  • This study develops ESP (Ensemble Streamflow Prediction) system by using medium-term numerical weather prediction model which is GDAPS(T213) of KMA. The developed system forecasts medium- and long-range exceedance Probability for streamflow and RPSS evaluation scheme is used to analyze the accuracy of probability forecasts. It can be seen that the daily probability forecast results contain high uncertainties. A sensitivity analysis with respect to forecast time resolution shows that uncertainties decrease and accuracy generally improves as the forecast time step increase. Weekly ESP results by using the GDAPS output with a lead time of up to 28 days are more accurately predicted than traditional ESP results because conditional probabilities are stably distributed and uncertainties can be reduced. Therefore, it can be concluded that the developed system will be useful tool for medium- and long-term reservoir inflow forecasts in order to manage water resources.

Assessment of Estimated Daily Intakes of Artificial Sweeteners from Non-alcoholic Beverages in Children and Adolescents (어린이와 청소년의 비알콜성음료 섭취에 따른 인공감미료 섭취량 평가)

  • Kim, Sung-Dan;Moon, Hyun-Kyung;Lee, Jib-Ho;Chang, Min-Su;Shin, Young;Jung, Sun-Ok;Yun, Eun-Sun;Jo, Han-Bin;Kim, Jung-Hun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.43 no.8
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    • pp.1304-1316
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    • 2014
  • The aims of this study were to estimate daily intakes of artificial sweeteners from beverages and liquid teas as well as evaluate their potential health risks in Korean children and adolescents (1 to 19 years old). Dietary intake assessment was conducted using actual levels of aspartame, acesulfame-K, and sucralose in non-alcoholic beverages (651 beverages and 87 liquid teas), and food consumption amounts were drawn from "The Fourth Korea National Health and Nutrition Examination Survey (2007~2009)". To estimate dietary intake of non-alcoholic beverages, a total of 6,082 children and adolescents (Scenario I) were compared to 1,704 non-alcoholic beverage consumption subjects (Scenario II). The estimated daily intake of artificial sweeteners was calculated based on point estimates and probabilistic estimates. The values of probabilistic artificial sweeteners intakes were presented by a Monte Carlo approach considering probabilistic density functions of variables. The level of safety for artificial sweeteners was evaluated by comparisons with acceptable daily intakes (ADI) of aspartame (0~40 mg/kg bw/day), acesulfame-K (0~15 mg/kg bw/day), and sucralose (0~15 mg/kg bw/day) set by the World Health Organization. For total children and adolescents (Scenario I), mean daily intakes of aspartame, acesulfame-K, and sucralose estimated by probabilistic estimates using Monte Carlo simulation were 0.09, 0.01, and 0.04 mg/kg bw/day, respectively, and 95th percentile daily intakes were 0.30, 0.02, and 0.13 mg/kg bw/day, respectively. For consumers-only (Scenario II), mean daily intakes of aspartame, acesulfame-K, and sucralose estimated by probabilistic estimates using Monte Carlo simulation were 0.52, 0.03, and 0.22 mg/kg bw/day, respectively, and 95th percentile daily intakes were 1.80, 0.12, and 0.75 mg/kg bw/day, respectively. For scenarios I and II, neither aspartame, acesulfame-K, nor sucralose had a mean and 95th percentile intake that exceeded 5.06% of ADI.

Warm Season Hydro-Meteorological Variability in South Korea Due to SSTA Pattern Changes in the Tropical Pacific Ocean Region (열대 태평양 SSTA 패턴 변화에 따른 우리나라 여름철 수문 변동 분석)

  • Yoon, Sun-kwon;Kim, Jong-Suk;Lee, Tae-Sam;Moon, Young-IL
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.1
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    • pp.49-63
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    • 2016
  • In this study, we analyzed the effects of regional hydrologic variability during warm season (June-September) in South Korea due to ENSO (El $Ni{\tilde{n}}o$-Southern Oscillation) pattern changes over the Tropical Pacific Ocean (TPO). We performed composite analysis (CA) and statistical significance test by Student's t-test using observed hydrologic data (such as, precipitation and streamflow) in the 113 sub-watershed areas over the 5-Major River basin, in South Korea. As a result of this study, during the warm-pool (WP) El $Ni{\tilde{n}}o$ year shows a significant increasing tendency than normal years. Particularly, during the cold-tongue (CT) El $Ni{\tilde{n}}o$ decaying years clearly decreasing tendency compared to the normal years was appeared. In addition, the La $Ni{\tilde{n}}a$ years tended to show a slightly increasing tendency and maintain the average year state. In addition, from the result of scatter plot of the percentage anomaly of hydrologic variables during warm season, it is possible to identify the linear increasing tendency. Also the center of the scatter plot shows during the WP El $Ni{\tilde{n}}o$ year (+17.93%, +26.99%), the CT El $Ni{\tilde{n}}a$ year (-8.20%, -15.73%), and the La $Ni{\tilde{n}}a$ year (+8.89%, +15.85%), respectively. This result shows a methodology of the tele-connection based long-range water resources prediction for reducing climate forecasting uncertainty, when occurs the abnormal SSTA (such as, El $Ni{\tilde{n}}o$ and La $Ni{\tilde{n}}a$) phenomenon in the TPO region. Furthermore, it can be a useful data for water managers and end-users to support long-range water-related policy making.

Evaluation of Metabolic Abnormality in Brain Tumors by In Viuo $^1$H MR Spectroscopy at 3 Tesla (3T 양성자 자기공명분광에 의한 뇌종양의 대사물질 이상소견)

  • Choe, Bo-Young;Jeun, Sin-Soo;Kim, Bum-Soo;Lee, Jae-Mun;Chung, Sung-Taek;Ahn, Chang-Beom;Oh, Chang-Hyun;Kim, Sun I.;Lee, Hyoung-Koo
    • Progress in Medical Physics
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    • v.13 no.3
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    • pp.120-128
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    • 2002
  • To investigate differences between the metabolic ratios of normal controls and brain tumors such as astrocytomas and glioblastoma multiforme (GM) by proton MR spectroscopy (MRS) at 37 high field system. Using 3T MRI/MRS system, localized water-suppressed single-voxel technique in patients with brain tumors was employed to evaluate spectra with peaks of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine/phosphocreatine (Cr) and lactate. On the basis of Cr, these peak areas were quantificated as a relative ratio. The variation of metabolites measurements of the designated region in 10 normal volunteers was less than 10%. Normal ranges of NAA/Cr and Cho/Cr ratios were 1.67$\pm$018 and 1.16$\pm$0.15, respectively. NAA/Cr ratio of all tumor tissues was significantly lower than that of the normal tissues (P=0.005). Cho/Cr ratio of glioblastoma multiforme was significantly higher than that of astrocytomas (P=0.001). Lactate was observed in all tumor cases. The present study demonstrated that the neuronal degradation or loss was observed in all tumor tissues. Higher grade of brain tumors was correlated with higher Cho/Cr ratio, indicating a significant dependence of Cho levels on malignancy of gliomas. This results suggest that clinical proton MR spectroscopy could be useful to predict tumor malignancy.

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