• 제목/요약/키워드: Variance Gamma

검색결과 89건 처리시간 0.026초

Variation in Flowering Time of Soybean after Irradiation

  • 김이훈;장병호
    • 한국작물학회지
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    • 제7권1호
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    • pp.129-132
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    • 1969
  • The polygenic variation in flowering time of soybean irradiated with Co$^{60}$ gamma ray evaluated in the R$_2$ generation. The genetic variance in the irradiation treatment was about four times that of the control. The basic possibility of selection for the early and the late in flowering time of soybean after irradiated with Co$^{60}$ was suggested in this paper.

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통계적 품질관리를 위한 왜도의 활용 (Utilization of Skewness for Statistical Quality Control)

  • 김훈태;임성욱
    • 품질경영학회지
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    • 제51권4호
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    • pp.663-675
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    • 2023
  • Purpose: Skewness is an indicator used to measure the asymmetry of data distribution. In the past, product quality was judged only by mean and variance, but in modern management and manufacturing environments, various factors and volatility must be considered. Therefore, skewness helps accurately understand the shape of data distribution and identify outliers or problems, and skewness can be utilized from this new perspective. Therefore, we would like to propose a statistical quality control method using skewness. Methods: In order to generate data with the same mean and variance but different skewness, data was generated using normal distribution and gamma distribution. Using Minitab 18, we created 20 sets of 1,000 random data of normal distribution and gamma distribution. Using this data, it was proven that the process state can be sensitively identified by using skewness. Results: As a result of the analysis of this study, if the skewness is within ± 0.2, there is no difference in judgment from management based on the probability of errors that can be made in the management state as discussed in quality control. However, if the skewness exceeds ±0.2, the control chart considering only the standard deviation determines that it is in control, but it can be seen that the data is out of control. Conclusion: By using skewness in process management, the ability to evaluate data quality is improved and the ability to detect abnormal signals is excellent. By using this, process improvement and process non-sub-stitutability issues can be quickly identified and improved.

Low-noise reconstruction method for coded-aperture gamma camera based on multi-layer perceptron

  • Zhang, Rui;Tang, Xiaobin;Gong, Pin;Wang, Peng;Zhou, Cheng;Zhu, Xiaoxiang;Liang, Dajian;Wang, Zeyu
    • Nuclear Engineering and Technology
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    • 제52권10호
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    • pp.2250-2261
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    • 2020
  • Accurate localization of radioactive materials is crucial in homeland security and radiological emergencies. Coded-aperture gamma camera is an interesting solution for such applications and can be developed into portable real-time imaging devices. However, traditional reconstruction methods cannot effectively deal with signal-independent noise, thereby hindering low-noise real-time imaging. In this study, a novel reconstruction method with excellent noise-suppression capability based on a multi-layer perceptron (MLP) is proposed. A coded-aperture gamma camera based on pixel detector and coded-aperture mask was constructed, and the process of radioactive source imaging was simulated. Results showed that the MLP method performs better in noise suppression than the traditional correlation analysis method. When the Co-57 source with an activity of 1 MBq was at 289 different positions within the field of view which correspond to 289 different pixels in the reconstructed image, the average contrast-to-noise ratio (CNR) obtained by the MLP method was 21.82, whereas that obtained by the correlation analysis method was 5.85. The variance in CNR of the MLP method is larger than that of correlation analysis, which means the MLP method has some instability in certain conditions.

The Role of Negative Binomial Sampling In Determining the Distribution of Minimum Chi-Square

  • Hamdy H.I.;Bentil Daniel E.;Son M.S.
    • International Journal of Contents
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    • 제3권1호
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    • pp.1-8
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    • 2007
  • The distributions of the minimum correlated F-variable arises in many applied statistical problems including simultaneous analysis of variance (SANOVA), equality of variance, selection and ranking populations, and reliability analysis. In this paper, negative binomial sampling technique is employed to derive the distributions of the minimum of chi-square variables and hence the distributions of the minimum correlated F-variables. The work presented in this paper is divided in two parts. The first part is devoted to develop some combinatorial identities arised from the negative binomial sampling. These identities are constructed and justified to serve important purpose, when we deal with these distributions or their characteristics. Other important results including cumulants and moments of these distributions are also given in somewhat simple forms. Second, the distributions of minimum, chisquare variable and hence the distribution of the minimum correlated F-variables are then derived within the negative binomial sampling framework. Although, multinomial theory applied to order statistics and standard transformation techniques can be used to derive these distributions, the negative binomial sampling approach provides more information regarding the nature of the relationship between the sampling vehicle and the probability distributions of these functions of chi-square variables. We also provide an algorithm to compute the percentage points of the distributions. The computation methods we adopted are exact and no interpolations are involved.

여성 비만의 유발유형별 일반 증상과 검사 특성 연구 (Characterizing of Four Obesity Types in Obese Women Based on the Questionnaire of Diseases and Physical Tests)

  • 진승희;최경미;박영배
    • 대한한의학회지
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    • 제25권1호
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    • pp.172-187
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    • 2004
  • Objectives : To characterize four types of obesity and to effectively improve the treatment of obesity through Oriental medicine Methods : At 00 Oriental Medical Center, 203 female subjects who intented to lose weight were requested to complete a questionnaire. These participants were also given physical tests. The Questionnaire consisted of questions both about general life style and obesity in oriental medicine framework. The physical tests were blood tests, a body composition via Inbody 2.0, and physical strength tests. One-way analysis of variance was done to compare the means of items and physical tests between four types of obesity. Duncan was used by post hoc test. Results : 1. Significant differences between obesity type III and obesity type IV in ever tried to lose weight, childhood obesity and excercise times were observed in the questionnaire of general life style(p<0.05). 2. Ducan test showed significant differences between four obesity types in diseases (p<0.05). 3. Significant differences between four obesity types in height, % body fat muscular endurance, soft lean mass, fat mass, Trigliceride, Total cholesterol and ${\gamma}-GTP$ were observed (p<0.05). Conclusions : Further clinical research is necessary in the four types of obesity explored. The diagnosis and treatment based on these types should be further studied.

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방사성 동위원소 심혈관 조영술을 이용한 단락량 측정법: 정확성에 영향을 미치는 인자 (Measurement of Shunt Amount Using Radionuclide Angiocardiography: Accuracy According to Level of Shunt and Associated Lesion)

  • 김양민
    • Nuclear Medicine and Molecular Imaging
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    • 제40권4호
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    • pp.200-204
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    • 2006
  • 목적: 산소포화도법과 비교하여 동위원소법을 이용한 Qp/Qs측정의 정확도를 알아보고, 이와 연관된 요인이 무엇인지, 추적 검사시 두 검사법의 결과를 서로 비교해서 사용할 수 있는지에 대하여 알아보고자 하였다. 대상 및 방법: 두 검사법으로 Qp/Qs를 측정한 207명의 환자를 대상으로 하였다. 동위원소를 이용한 방법은 폐에 관심영역을 설정하여 시간-방사능 곡선을 얻어서 gamma variate model에 적용하여 면적으로부터 Qp/Qs를 구하였다. 환자의 연령, 좌우 단락의 종류와 동반된 질환 등에 따라서 방사성 동위원소 조영술과 심도자술로 얻어진 Qp/Qs의 상관계수와 일치도를 분석하였다. 결과: 동위원소 검사법과 심도자술로 얻어진 Qp/Qs의 평균치는 각각 $1.85{\pm}0.50,\;1.74{\pm}0.51$이며, 두 검사법으로 얻은 Qp/Qs의 상관계수는 0.86 (p<0.001)으로 강한 상관관계를 보였다. Bland-Altman 분석에서 두 검사법에 의한 Qp/Qs의 일치의 한계값은 $-0.42{\sim}0.63$, 범위는 1.05였다. 심실중격 결손증 환자에서는 상관계수가 0.90으로 강한 상관관계를 보였으며, 일치의 한계값은 $-0.29{\sim}0.45$ 였다. 심방중격 결손증, 심실중격 결손증, 동맥관 개존증 환자와 삼첨판 부전증과 승모판 부전증이 동반된 환자에서의 상관계수는 각각 0.78, 0.90, 0.84, 0.63, 0.44 였으며, 일치의 범위는 1.52, 0.74, 0.96, 1.57. 1.50이였다. 결론: 동위원소 검사법과 심도자술로 얻어진 Qp/Qs는 전체적으로 좋은 상관관계를 보이나 일치의 한계값이 크므로 추적 검사시 서로 호환하여 사용하기 어렵다. 방실판막 부전증이 동반된 경우에는 낮은 상관관계와 낮은 일치도를 보였다.

지진 피해자의 외상 후 성장에 영향을 미치는 요인들 간의 구조모형 (A Structural Equation Model of Factors Influencing Posttraumatic Growth of Earthquake Victims)

  • 곽민영
    • 지역사회간호학회지
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    • 제30권3호
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    • pp.345-356
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    • 2019
  • Purpose: The purpose of this study is to construct and test a structural equation model of posttraumatic growth (PTG) of earthquake victims based on Tedeschi and Calhoun's model (2004). Methods: Data were collected from 195 earthquake victims living in K. City. The exogenous variables include distress perception, resilience, and social support, and the endogenous variables include intrusive rumination, deliberate rumination, and posttraumatic growth. For data analysis, descriptive statistics, factor analysis, and structural equation modeling were performed. Results: The modified model showed a good fitness to the data. Moreover, 6 of the 9 paths of the final model were statistically significant, which include PTG affected by deliberate rumination (${\beta}=.58$, p<.001), resilience (${\gamma}=.18$, p=.001), and distress perception (${\gamma}=.20$, p=.002). These predictors explain 51.8% of variance in posttraumatic growth. Conclusion: Based on the results of this study, it is necessary to develop and disseminate preventive intervention programs to increase the resilience of earthquake-prone communities. In addition, after exposure to a community-scale traumatic event such as earthquake, we should provide social supports to alleviate distress perception and transition from intrusive rumination to deliberate rumination so that we can seek new meaning from the earthquake and facilitate posttraumatic growth.

지구통계학적 방법에 의한 영광원전주변 토층내 Cs-137 및 K-40 측정 결과의 해석 (Geostatistical Interpretation of Cs-137 and K-40 Result of the Lithosphere in the Vicinity of Youngkwang Nuclear Power Plant)

  • 김경웅;이재석;문승현;박철승;고일원;고은정;조병옥;정철영;전수열
    • 자원환경지질
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    • 제35권6호
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    • pp.545-552
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    • 2002
  • 광주과학기술원 에너지환경연구센터에서는 2000년 한해 동안 원자력발전소 주변 환경방사선 조사계획에 의거하여 영광원자력발전소 부지외부 및 비교지점에서 토양, 하천토 및 해저토 등 환경방사능 시료에 대한 감마선 방출핵종 분석을 수행하였다. 분석결과 토양과 하천토 및 해저토에서 인공핵종인 Cs-137이 검출되었으나 지난 3년간(1997-99)의 측정치인 평상범위 이내의 값이었고, 원전과 관계없는 일반지역에서 검출되는 수준과도 동일하며, 반감기가 짧은 Cs-134는 전혀 검출되지 않은 것으로 보아 원전가동에 의한 영향이 아님을 알 수 있다. 환경시료 측정에 대한 품질관리를 위해 임의로 선정된 가마미인근에서 해저토 시료를 각각 5지점에서 중복시료로 채취하석 상대 검출효율이 각각 30%, 45%인 2대의 HPGe Gamma-ray Spectroscope로 동시에 분석하여 환경방사선 측정자료와 분석의 신뢰도를 향상시키기 위한 지구통계학적인 연구를 수행하였다. 이를 위해서 두 가지 요인을 설정하여 시료분석방법과 채취지점의 차이를 이원배치 분산분석을 수행하였다. Two-way ANOVA 결과 Cs-137 및 K-40의 경우 시료채취 지점의 차이에 의한 분산만이 유효하며, 시료채취 및 분석과정에서의 생기는 오차는 무시할 만하여 지금까지 수행되어진 시료채취 및 분석방법은 신뢰할 만하다고 할 수 있었다.

간호사의 희망, 감사성향, 일터영성이 조직시민행동에 미치는 영향 (Effects of Hope, Grateful Disposition, Workplace Spirituality on Organizational Citizenship Behavior among Nurses)

  • 임소희;최은덕
    • 한국산학기술학회논문지
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    • 제18권2호
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    • pp.277-286
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    • 2017
  • 본 연구는 간호사의 희망과 감사성향, 일터영성이 조직시민행동정도를 파악하고, 조직시민행동에 미치는 영향요인을 분석하여 바람직한 간호조직문화를 형성 및 증진시켜 간호조직의 효율적이고 경쟁력 있는 인적자원관리방안을 제시하고, 중재방안을 마련하는데 기초자료를 제공하고자 시도되었다. 서울 및 경기도 소재 종합병원 이상의 4개 병원에서 근무하는 간호사 147명을 대상으로 설문조사하였고, 수집된 자료는 SPSS 18.0 프로그램을 이용하여 t-test와 ANOVA, Person's correlation coefficients, multiple stepwise regression으로 분석하였다. 연구결과 간호사의 희망(${\gamma}=.22{\sim}.36$, p<.001), 감사성향(${\gamma}=.38$, p<.001), 일터영성(${\gamma}=.38{\sim}.54$, p<.001), 조직시민행동 간에는 정적 상관관계를 보였다. 또한, 일터영성(${\beta}=.54$, p<.001), 이직희망(${\beta}=.12$, p<.001), 희망(${\beta}=.09$, p<.001), 감사성향(${\beta}=.08$, p<.001)은 조직시민행동에 유의한 영향을 주었으며, 설명력은 41.6%이었다. 본 연구는 간호조직에서 아직 초기단계의 연구가 진행되고 있는 일터영성에 대한 기초이론을 체계화하였고, 간호사의 조직시민행동을 유발시키기 위해 간호사의 희망, 감사성향, 일터영성을 높일 수 있는 다양한 교육 프로그램과 지원 제도가 요구된다.

초등학생의 식품위생안전에 대한 지식, 태도 및 실천에 관한 연구 (Knowledge, Attitudes, and Practices of Elementary School Children Regarding Food Hygiene and Safety)

  • 김종규;김중순
    • 한국환경보건학회지
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    • 제39권3호
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    • pp.256-267
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    • 2013
  • Objectives: The purpose of this study was to evaluate food hygiene and safety knowledge, attitudes, and practices (KAP) among the elementary school children, and furthermore, to explain the interrelations among these three variables. A second purpose was to compare gender differences of KAP. Methods: A self-administered, structured questionnaire was designed and completed by 376 elementary school children. A five-point Likert scale with twenty questions was used to gather information. Data was analyzed by frequency analysis, Pearson's correlation and analysis of variance or Student's t-test. Results: Children generally had good knowledge of food hygiene and safety, and knowledge of children was superior to the attitudes and also to their practices (p < 0.05). The attitude score was mediated between knowledge and practice scores. Significant differences (p < 0.05) were found between boys and girls in an item of knowledge, three items of attitudes, and six items of practices. A significant positive correlations were observed between knowledge and practices (${\gamma}$ = 0.70, p < 0.001), and between attitudes and practices (${\gamma}$ = 0.45, p < 0.001), as well as between attitudes and practices (${\gamma}$ = 0.51, p < 0.001), revealing that increased knowledge and even attitudes toward food hygiene safety could result in positive change in practices or behaviors. Conclusions: The results of this study indicate that despite good knowledge and attitudes of children, their practices toward food hygiene and safety are not acceptable. Gender differences in practices were highlighted. In order to create effective educational interventions on the food hygiene and safety of children, a better understanding of their awareness and the required related information is necessary.