• 제목/요약/키워드: two sample t-test

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Tedlar-bag 시료채집법을 이용한 황화합물의 경시적 농도 변화특성: 시료의 생성방식의 차이에 따른 비교연구 (Storage stability of reduced sulfur gases in Tedlar bag sampler: Test of two different storing approaches)

  • 조효재;김기현
    • 분석과학
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    • 제24권3호
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    • pp.212-218
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    • 2011
  • 본 연구에서는 5종류의 황화합물질($H_2S$, $CH_3SH$, DMS, $CS_2$, DMDS)을 10 ppb (nmol/mol) 수준으로 포함하는 기체상 표준시료를 Teldlar bag에 담은 후 시차를 두고 30일 동안의 기간에 걸쳐 농도변화를 분석하였다. 황성분의 시간적 안정도를 파악하기 위해, 백에 보존한 시료의 보존방식과 분석시점에 대한 결정을 두 가지 상이한 접근방식으로 비교하였다. 이를 통해 시료의 장기적 보관방식과 분석시스템의 일관성에 대한 특성을 동시에 평가하고자 하였다. 이를 위하여, 첫 번째로 전체 보관기간 동안 분석할 시료를 일괄적으로 준비하여 이들을 시간대별로 하나씩 분석하는 Forward(F)보전방식으로 진행하였다. 두 번째로는 시료를 시간의 경과에 따라 순차적으로 준비하고, 종료시점에 모두 일괄적으로 분석하는 Reverse(R)방식으로 접근하였다. 이를 유의수준 90% 기준으로 t-테스트를 적용하여, 두 가지 분석방식의 자료들간에 차이점을 짝비교 방식으로 검정하였다. 이때 $H_2S$, $CH_3SH$, DMDS성분의 결과는 유의한 차이가 존재하는 것으로 나타났다. 본 실험의 결과, 분자량이 가벼운 황성분들($H_2S$$CH_3SH$)과 무거운 황성분들(DMS, $CS_2$, DMDS)간의 경시적 안정도에는 현저한 차이가 존재하는 것을 확인였다. 그러나 두 방식 모두 농도가 감소하는 상대적 경향은 성분 별로 일치하였다.

시험과 사회적 지지에 따른 대학생의 스트레스 호르몬, 림프구 및 호중구의 변화 (Changes in Stress Hormone, Lymphocytes, and Neutrophils Related to Examination and Social Support in University Students)

  • 김주현;채영란
    • 성인간호학회지
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    • 제22권1호
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    • pp.11-18
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    • 2010
  • Purpose: The purpose of the study was to identify levels of anxiety, stress hormone, lymphocytes, and neutrophils of the nursing students before an examination and to examine effects of social support on those variables related to taking examinations. Methods: Thirty eight healthy nursing students participated. They completed the questionnaire including state anxiety, test anxiety (VAS scale) and social support two weeks before the exam and again just before the exam. Simultaneously, a venous sample for ACTH, cortisol, lymphocytes & neutrophils count was drawn by a trained nurse. Descriptive statistics, paired t-test, student t-test, and Pearson's correlation with SPSS/WIN 14.0 were used to analyze the data. Results: Test anxiety scores and cortisol level on the exam day showed a significant increment compared with those on the non-exam day. The participants with higher levels of total social support scores showed significantly lower state anxiety on the exam day than those with lower levels of total social support scores. Conclusion: These data indicate a possible alteration in cortisol responsiveness to academic stress in nursing students. Social support would play an important role in modulation of academic stress.

제2종(第2種) 중단(中斷) 자료(資料)에서 두 모수지수분포(母數指數分布)의 베이지안 추정(推定) (Bayesian Estimations for the Two-parameter Exponential Model under the Type-II Censoring)

  • 김헌주;윤용화;고정환
    • Journal of the Korean Data and Information Science Society
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    • 제4권
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    • pp.65-74
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    • 1993
  • Suppose that we have two populations(or systems), say ${\Pi}_{1}\;and\;{\Pi}_{2}$, to be tested. A random sample of size n from each population is taken and the test for each system will be terminated when the first r failures among n random samples are observed. This kind of test is caned the type-II censored (or item-censored) testing without replacement. Under this scheme we consider the problem of estimating the unknown parameters of interests and the reliability for a given time t for each population.

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발전설비 보일러 튜브 용접부의 잔여수명평가 신뢰성 향상을 위한 기계적 물성 변화 연구(SA213-T12) (A Study on Mechanical Properties Changes to Improve the Confidence of Remaining Life Evaluation for the Weldment of Power Plant Boiler Tube(SA213-T12))

  • 오병진;장중순
    • Journal of Welding and Joining
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    • 제32권3호
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    • pp.102-107
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    • 2014
  • Boiler equipment in power plant is always being operated in harsh conditions and severely exposed to the extreme environment of high temperature. Therefore periodically the state of devices should be checked, diagnosed, and analyzed to ensure the reliability of the equipment. Traditionally, such a diagnosis is based one or two physical properties of the sample taken from the equipment like hardness, microstructure, etc.. However, to enhance the confidence of the diagnosis, it is necessary to synthesize those properties together. This paper is to propose such a synthetic procedure for SA213-T12(1Cr-0.5Mo) which was developed to be used in $565^{\circ}C$ below condition. Creep test and accelerated degradation test were performed simultaneously, and the physical properties such as microstructure, tensile strength, yield strength, hardness, and indentation properties were measured. This paper proposes a method of determining the remaining life by quantitative comparison. It will provide the basis of evaluating life assessment more objective and reliable.

Psychological Treatment for Pain Among Cancer Patients by Rational-Emotive Behavior Therapy - Efficacy in both India and Iran

  • Mahigir, Foroogh;Khanehkeshi, Ali;Karimi, Ayatollah
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권9호
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    • pp.4561-4565
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    • 2012
  • The aim of the present study is to find out the influence of rational-emotive behavior therapy (REBT) on pain intensity among cancer patients in India and Iran. The study followed a quasi-experimental, pre-post test, carried out with a sample of 88 cancer patients, aged 21-52 years, referred to the Baharat cancer hospital of Mysore in India and Shahidzade hospital of Behbahan in Iran. They were randomly assigned to the experimental (n=India 21; Iran 22) and control (n=India 22; Iran 23) groups. Pain was measured with the McGill Pain Questionnaire-MPQ (1975), the intervention by REBT has given to the experimental group for 45 days (ten sessions) and at the end of intervention, the pain of patients was again evaluated. Concerning to hypothesis of the study, two independent sample T test and three ways mixed ANOVA is used to analyze the data. Results showed that the experimental group in post test had less pain than the control group, but there were no statistically significant differences between Indian and Iranian patients in pain perception. With respect the outcome of study, it has realized that REBT can be used in hospitals and other psychological clinics to reduce the pain of cancer patients.

익기보혈탕(益氣補血湯)이 C57BL/6 마우스의 육모(育毛)촉진 및 Cytokine 변화에 미치는 영향 (Effect of Yikgeebohyul-tang (Yiqib$\check{u}$xu$\grave{e}$-tang) on Hair Regrowth and Cytokine Changes on Hair-Removed C57BL/6 Mice)

  • 홍정애;송미연;최인화;손락원;정석희
    • 대한한의학회지
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    • 제31권1호
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    • pp.138-152
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    • 2010
  • Objective: Yikgeebohyul-tang (Yiqib$\check{u}$xu$\grave{e}$-t$\bar{a}$ng) is one of the representative prescriptions for invigoration of vitality and nourishing of the blood. This study was carried out to investigate the effects of Yikgeebohyul-tang (Yiqib$\check{u}$xu$\grave{e}$-t$\bar{a}$ng) on hair regrowth and cytokine changes in a shaving model of C57BL6 mice. Method: Five-week-old mice were acclimated for 1 week at a temperature between $21-23^{\circ}C{\acute{E}}$, 40-60% relative humidity, and 12h of a light/dark cycle before beginning of the experiment. There were two groups including normal saline (control) and a positive control of oral intake of Yikgeebohyul-tang (Yiqib$\check{u}$xu$\grave{e}$-t$\bar{a}$ng) extract (sample) in 18 female mice. The test compounds were topically treated once a day over 14 days. The hair regrowth was photographically and histologically determined during the experimental period of 14 days. Revelation of TGF-${\beta}1$ and EGF were also determined using immunohistochemistry. In addition to that, IFN-$\gamma$, IL-4 and IL-10 were determined in serum. Results: Hair regrowth in the sample group was promoted earlier and faster than the control group, as shown by concentrations of hairs and thick-hair ratio in the sample group. TGF-${\beta}1$ was not revealed in either control or sample group. EGF was strongly positive in out root sheath of some thick hair of the sample group. Serum IFN-$\gamma$ was significantly decreased in the sample group compared with the control group at 7 experimental days. However, it was not significantly decreased at 14 experimental days. Serum IL-4 was significantly increased in the sample group compared with the control group at 7 experimental days. However, it was not significantly decreased at 14 experimental days. Serum IL-10 was decreased in the sample group compared with the control group, but with no real statistical significance. Conclusion: These results suggest that Yikgeebohyul-tang (Yiqib$\check{u}$xu$\grave{e}$-t$\bar{a}$ng) has hair growth promoting activity and it can be used for treatment of alopecia. Also, these effects relate to EGF revelation of hair roots, a decrease in serum IFN-$\gamma$, and an increase of serum IL-4.

임신성 당뇨병 임부와 정상 임부의 스트레스, 우울, 피로 및 수면의 질에 관한 서술적 조사연구 (A descriptive survey study of stress, depression, fatigue & sleep quality in gestational diabetes mellitus and normal pregnancy)

  • 황인명;허명행
    • 한국융합학회논문지
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    • 제12권8호
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    • pp.369-379
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    • 2021
  • 본 연구는 임신성 당뇨병 임부와 정상 임산부의 스트레스, 우울, 피로 및 수면의 질을 비교하기 위한 서술적 조사연구이다. 연구대상은 연령, 임신주수, 출산 횟수가 일치하는 임신성 당뇨병 임부 49명과 정상 임부 51명이었다. 자료수집은 구조화된 설문지, 숫자 척도, Canopy9 RSA(IEMBIO, Gangwondo, Korea)장비를 사용하여 측정하였다. 자료 분석은 SPSS for window version 24.0을 이용하여 빈도, 백분율, 평균과 표준편차 Independent two sample t-test, Fisher's exact test, x2-test로 분석하였다. 본 연구 결과 임신성 당뇨병 임부는 임신 전 체중(t=3.698, p<.001)이 높고 임신 중 스트레스(t=4.505, p<.001), 우울(t=4.564, p<.001), 피로(t=3.709, p<.001)가 높았기 때문에 임신 전 체중 관리가 중요하며, 임신성 당뇨병 임산부의 스트레스, 피로, 우울을 완화하는 간호가 필요하다.

Efficacy of local hyaluronidase administration in guided bone regeneration surgery: a randomized controlled trial

  • Kwoen, Min-Jeong;Choi, Yong-Hoon;Kim, Keun-Suh;Chang, Na-Hee;Kim, Young-Kyun;Lee, Hyo-Jung
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제47권2호
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    • pp.91-98
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    • 2021
  • Objectives: Hyaluronoglucosaminidase (hyaluronidase) increases the local intercellular permeability of the peripheral lymphatic channel and capillaries, which may help reduce edema. In the present study, the effects of hyaluronidase on postoperative edema and pain reduction were evaluated. Materials and Methods: The study included 38 patients who underwent guided bone regeneration (GBR) surgery before implantation. Patients were randomly assigned to either the control group (n=20) or the test group (n=18). Hyaluronidase was injected into the GBR site of subjects in the test group. Postoperative edema was evaluated by measuring the distance between specific facial landmarks immediately after surgery (T1) and 2-4 days after surgery (T2). The degree of pain at T2 and at 10-14 days after surgery (T3) was assessed. Results: In the test group, the degree of swelling was lower than in the control group, however, only two measurements, from the tragus to the mouth corner and from the outer canthus to the mouth corner, showed statistically significant differences (P=0.012 and P=0.001, respectively). The anti-edema effect of hyaluronidase was more effective in the maxilla than in the mandible. In the maxilla, the percentage of facial swelling was significant for three measurements. However, in the mandible, the percentage of facial swelling was significant for only one measurement. Low levels of pain that were similar at T2 and T3 were reported in both groups. Conclusion: The results indicate the degree of swelling was lower in the test group and hyaluronidase appeared to be more effective in the maxilla. The degree of pain reduction was similar between groups. Further in vivo and randomized controlled trials with larger sample sizes are warranted.

Determining the Knowledge of Women and Their Attitudes Regarding Gynecological Cancer Prevention

  • Bekar, Mine;Guler, Handan;Evcili, Funda;Demirel, Gulbahtiyar;Duran, Ozlem
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권10호
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    • pp.6055-6059
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    • 2013
  • The current study determines the knowledge of female course attendees of the "Municipality Cultural Center for Women", located in the city center of Sivas, Turkey, and their attitudes regarding gynecological cancer prevention. The participants of the study include 497 women attending one of the two Municipality Cultural Centers situated in the city center of Sivas. In this study, the sample was not selected; all participants were encompassed within the scope of our research. A total of 418 female course attendees who volunteered to participate in the research were identified as the sample. The data were collected during the months March-June 2011, by a questionnaire developed by the researchers. To compare the distribution of the collected data "Anova", "two independent t test examples" and "chi square test" were used. The research indicates that 45.1% of the women had had gynecological examination as a consequence of a physical disorder. The reason for 54.9% of the women to have gynecological examination is to have been scanned to check for gynecological cancer, 51.2% had a pap smear test. Some 34.9% of them had obtained information about cervical cancer, 39.7% via radio, television or internet and 36.3% from a doctor. Age, education level and marital status of the women participating in this study demonstrated statistically significant correlations (p<0.05) with gynecological examination and undergoing a pap smear test.

국내 사례로 살펴보는 국방체계 개발의 신뢰성을 높이기 위한 시험평가 방안 (Effective Test and Evaluation Approaches for Reliable Defense Systems Development examined through Domestic Defense Cases)

  • 서경민;이찬영;방경운;이동철;최우영;김탁곤
    • 대한조선학회논문집
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    • 제53권2호
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    • pp.127-134
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    • 2016
  • This paper presents practical issues for test and evaluation(T&E) methods to develop defense systems. Our argument is motivated by several domestic defense cases and the cases lead us to discuss two main factors for reliable defense systems development: 1) statistical approaches and 2) technical schemes. Specifically, statistical approaches enable to provide credible interpretations about T&E results in the decision-making process. With practical T&E results of the “Red Shark” torpedo, we performed statistical hypothesis tests and suggest a minimum sample size to accept the hypothesis. Next, technical schemes have more direct effects on improving reliability of developed defense systems and we shortly introduce tools development for systems verification that is required to integrate several sub-systems, e.g., combat, sensor, weapon, and communication systems, within a defense system. We additionally summary some domain cases using modeling and simulation techniques for successful T&E. In closing, we expect that the paper shows empirical investigation and lessons learned with these two practical issues, which provides a guide those who desire to make decisions about reliable defense systems development.