• Title/Summary/Keyword: Statistical power

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The Korea Cohort Consortium: The Future of Pooling Cohort Studies

  • Lee, Sangjun;Ko, Kwang-Pil;Lee, Jung Eun;Kim, Inah;Jee, Sun Ha;Shin, Aesun;Kweon, Sun-Seog;Shin, Min-Ho;Park, Sangmin;Ryu, Seungho;Yang, Sun Young;Choi, Seung Ho;Kim, Jeongseon;Yi, Sang-Wook;Kang, Daehee;Yoo, Keun-Young;Park, Sue K.
    • Journal of Preventive Medicine and Public Health
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    • v.55 no.5
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    • pp.464-474
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    • 2022
  • Objectives: We introduced the cohort studies included in the Korean Cohort Consortium (KCC), focusing on large-scale cohort studies established in Korea with a prolonged follow-up period. Moreover, we also provided projections of the follow-up and estimates of the sample size that would be necessary for big-data analyses based on pooling established cohort studies, including population-based genomic studies. Methods: We mainly focused on the characteristics of individual cohort studies from the KCC. We developed "PROFAN", a Shiny application for projecting the follow-up period to achieve a certain number of cases when pooling established cohort studies. As examples, we projected the follow-up periods for 5000 cases of gastric cancer, 2500 cases of prostate and breast cancer, and 500 cases of non-Hodgkin lymphoma. The sample sizes for sequencing-based analyses based on a 1:1 case-control study were also calculated. Results: The KCC consisted of 8 individual cohort studies, of which 3 were community-based and 5 were health screening-based cohorts. The population-based cohort studies were mainly organized by Korean government agencies and research institutes. The projected follow-up period was at least 10 years to achieve 5000 cases based on a cohort of 0.5 million participants. The mean of the minimum to maximum sample sizes for performing sequencing analyses was 5917-72 102. Conclusions: We propose an approach to establish a large-scale consortium based on the standardization and harmonization of existing cohort studies to obtain adequate statistical power with a sufficient sample size to analyze high-risk groups or rare cancer subtypes.

Study on Accuracy Improvement of Predictive Model of Arsenic Transfer from Contaminated Soil to Polished Rice (오염토양으로부터 백미로 전이되는 비소함량 예측모델의 정확도 향상 연구)

  • Jo, Seungha;Han, Hyeop-Jo;Lee, Jong-Un
    • Economic and Environmental Geology
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    • v.55 no.4
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    • pp.389-398
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    • 2022
  • Many studies have been conducted to accurately predict the correlations between As and heavy metals content in contaminated soil and cultivated crops; however, due to the low correlation between the two, few clear results were obtained to date. This study aimed to create statistical models that predict the As content transferred from soil to polished rice, considering the physicochemical properties of the soil, as well as the total content and the single-extracted content of As in the soil. Predictive models were derived through regression analysis while sequentially classifying soil samples according to pH, soluble As content by single extraction, and organic matter content of the soil. The correlation coefficients between the As content in 80 polished rice and total As content and Mehlich soluble As content in the soil were low, 0.533 and 0.493, respectively. However, the models derived after sequential classification of the soil by pH, a ratio of total As content to Mehlich soluble As content, and organic matter content greatly increased the predictive power; ① 0.963 for 13 soils with a pH higher than 6.5, ② 0.849 for 15 soils with pH lower than 6.5 and a high ratio of AsTot/AsMehlich, ③ 0.935 for 30 soils with pH lower than 6.5, a high ratio of AsTot/AsMehlich, and organic matter content lower than 8.5%. The suggested prediction model of As transfer from soil to polished rice derived by soil classification may serve as a statistically significant methodology in establishing a rice cultivation standard for arsenic-contaminated soil.

The Effect of Rice Co-Brand Assets, Trust, and Attachment on Loyalty (쌀 공동브랜드의 자산, 신뢰, 애착이 충성도에 미치는 영향)

  • Kim, Shine
    • Journal of Digital Convergence
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    • v.20 no.5
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    • pp.401-410
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    • 2022
  • This study deals with the relationship among trust, attachment and brand loyalty of agricultural products' rice co-brands, which are the staple food of the people. The research method established the hypothesis of the study under the foundation of prior research and developed the survey. The subjects of the study were distributed, retrieved, and analyzed the survey of 163 rice farmers in Buyeo-gun, Chungcheongnam-do. The empirical analysis results show that: First, hypothesis 1 of the brand awareness and image that "rice brand assets will be a positive relationship to trust" were statistically adopted. In particular, statistical t values showed a difference in consumer confidence over recognition>images. Second, hypothesis 2 of the trust of agricultural rice brands will be a positive influence on attachment and loyalty' statistically supported. In this regard, brand trust was higher in loyalty than attachment. Third, the attachment of agricultural products to rice brands will be a positive influence on loyalty,' was statistically supported. The strategic implications of this study are as follows. First, consumers should be given clues of trust(ex, GAP of Natioanl Approval Licesing, Fam Tour) as they distrust the perceived quality of the rice in the market. Second, the effect of the origin of rice is questionable, so the spread of the production power system should prevent the mixing of rice varieties, that is the spread of the production history systems.

Effects of Caffeine lntake and Stress on Sleep Quality in University Students (대학생의 카페인 섭취와 스트레스가 수면의 질에 미치는 영향)

  • Kim, Sang Hyeon;Gwon, Su A;Kwon, Yu Jin;Kim, Se In;Kim, Ye Jin;Oh, Hye Ran;Ha, Su Young;Cha, Nam Hyun
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.5
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    • pp.161-169
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    • 2022
  • The purpose of this study performed to confirm the effect of caffeine intake and stress on sleep quality of college students. Research respondents and data collection were conducted on 269 college students through Google questionnaires from February 14 to March 13, 2022, and the research design is a descriptive survey study. Statistical analysis was performed using the SPSS 27.0 version as t-test and one way ANOVA. As a result of the study, it was found that most college students consume more caffeine than the average daily caffeine intake of Korean adults, although it is far below the recommended daily caffeine intake of Korean adults. The quality of sleep of college students is stress (r=.32, p=<).001) and caffeine intake (r=.204, p=.001). It was found that there was a positive correlation. Factors affecting sleep quality are body mass index (β=.1.19, p<.001) Stress (β=.3.37, p<.001), smoking (β=-.18, p=.001), caffeine intake (β=.15, p=.005) It was in order, and the explanatory power of the model was 24.8%.

The Effects of Professional Sports Visitor Factors on Team Image, Team Satisfaction, and Team Reputation: Focusing on professional basketball visitors in 2021-2022 (프로스포츠 관람요인이 구단 이미지, 구단 만족, 구단 평판에 미치는 영향: 2021-2022 프로농구 관람객을 중심으로)

  • Mookyung Jang
    • Journal of Service Research and Studies
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    • v.12 no.2
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    • pp.117-134
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    • 2022
  • This study conducted a survey on visitors who visited the 2021-2022 KBL Professional Basketball Stadium in Wonju to understand how professional sports viewing factors affect the club image, club satisfaction, and club reputation. As factors for watching professional sports, four factors were considered: stadium, game situation, spectating cost, and spectator promotion. A total of 450 questionnaires were distributed and 411 questionnaires excluding 39 questionnaires were used as the final analysis data. For the effective questionnaire survey, After analyzing the purpose and purpose of the research, participants were asked to collect data. The collected data were analyzed using SPSS statistical package after data coding and cleaning process. The results of this study are as follows. First, the effect of professional sports viewing factor on brand image was 45.1%, and the factor of pro sports viewing was significant in stadium, competition situation, and promotion of viewing, and had no effect on viewing cost. Second, the influence of professional sporting factor on the satisfaction of the team was 42.5% in explaining power, which was significant in the stadium, the competition situation, the cost of visiting, and promotion of viewing. Third, the influence of professional sports viewing factor on team reputation was 62.1%, and the factor of professional sports viewing was significant in promoting stadium, visiting cost, and viewing, and had no effect on economic situation. The implication of this study is that in order to increase the brand value of the club, it is much more effective to increase the quality of facilities and food and beverages and to activate events for the audience than to lower the cost of viewing.

The Effect of Positive Psychological Capital on the Communication Competence and Job Satisfaction of Geriatric Hospital Nurses (긍정심리자본이 노인요양병원 간호사의 의사소통능력과 직무만족에 미치는 영향)

  • Jung, E-Hwa
    • Journal of Korea Entertainment Industry Association
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    • v.13 no.1
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    • pp.235-243
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    • 2019
  • The purpose of this study was to positive psychological capital on the Communication competence and Job Satisfaction, of Geriatric hospital Nurses. Data were collected using questionnaires from 255 Geriatric hospital Nurses located in G Metropolitan City with over one year career experiences. The collected data was analyzed by descriptive statistics, pearson's correlation coefficient and stepwise multiple regression using IBM SPSS 23.0 program. The mean scores for the positive psychological capital(3.23±.49), Communication competence(3.56±.47) and job satisfactions (2.88±.55). Second, positive psychological capital positive mentality has positive correlations with communication capital and job satisfaction. Third, Optimism have statistical significance on communication competence in 33% level. Hope has positive correlations with job satisfaction in 6% of an explanatory power. As a conclusion, it is necessary to lower the turnover rate of nursing homes for the elderly and increase the job satisfaction effect, many factors related to positive psychological capital are continuously found in order to solve the nursing workforce of geriatric nursing hospitals.

The Effects of Ankle Strengthening Exercise and Toe Taping Walk Training to Lower Body Exercise Function (발목강화운동과 무지테이핑 걷기훈련이 하체운동기능에 미치는 영향)

  • Ji-Su Kang;Jong-Bok Lee;Il-Young Cho;Hyun-Tae Kim;Jong-Hyuck Kim;In-Dong Kim;Jae-Joong Kim;Jeong-Beom Park
    • Journal of Industrial Convergence
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    • v.21 no.7
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    • pp.51-63
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    • 2023
  • This study aimed to verify the effects of a 4-week program of ankle-strengthening exercise and toe-taping walk exercise on the basic lower body strength and walking to examine the benefits of the two exercises. The subjects involved 30 women in their 20s enrolled in university A. The subjects were equally divided into three groups - ankle-strengthening exercise group, toe-taping walk exercise group, and control group. The subjects were instructed to massage and do ankle-strengthening exercises using a towel, massage ball, and CRT, for 60 minutes, 3 times a week. They also taped their hallux valgus using a kinesiology tape and walked for 20 minutes with white tape applied. To sum up, the 4-week ankle-strengthening exercise and toe-taping walk exercise were identified to have a partial statistical significance on the basic lower body strength (muscular strength, power, and balance) and walking (length of gait line, plantar pressure, and COP) of women in their 20s. Therefore, the study confirmed the effects of ankle-strengthening exercises and toe-taping walk exercise on the lower body exercise function, and it is considered that further studies should be conducted on more various effects of the exercises by subdividing them into different pain locations and orthomechanic findings.

Dynamic Load Allowance of Highway Bridges by Numerical Dynamic Analysis for LRFD Calibration (LRFD 보정을 위한 동적해석에 의한 도로교의 동적하중허용계수)

  • Chung, Tae Ju;Shin, Dong-Ku;Park, Young-Suk
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.3A
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    • pp.305-313
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    • 2008
  • A reliability based calibration of dynamic load allowance (DLA) of highway bridge is performed by numerical dynamic analysis of various types of bridges taking into account of the road surface roughness and bridge-vehicle interaction. A total of 10 simply supported bridges with three girder types in the form of prestressed concrete girder, steel plate girder, and steel box girder is analyzed. The cross sections recommended in "The Standardized Design of Highway Bridge Superstructure" by the Korean Ministry of Construction are used for the prestressed concrete girder bridges and steel plate girder bridges while the box girder bridges are designed by the LRFD method. Ten sets of road surface roughness for each bridge are generated from power spectral density (PSD) function by assuming the roadway as "Average Road". A three dimensionally modeled 5-axle tractor-trailer with its gross weight the same as that of DB-24 design truck is used in the dynamic analysis. For the finite element modeling of superstructure, beam elements for the main girder, shell elements for concrete deck, and rigid links between main girder and concrete deck are used. The statistical mean and coefficient of variation of DLA are obtained from a total of 100 DLA results for 10 different bridges with each having 10 sets of road surface roughness. Applying the DLA statistics obtained, the DLA is finally calibrated in a reliability based LRFD format by using the formula developed in the calibration of OHBDC code.

A Study on Antecedents of Suicidal Ideation among Korean Older Adults: A test of the Stress-diathesis Model (노인의 자살 생각에 영향을 미치는 선행요인에 관한 연구: 스트레스 소질 모델(Stress-diathesis Model)을 중심으로)

  • Ahn, Joonhee;Chun, Miae
    • 한국노년학
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    • v.29 no.2
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    • pp.489-511
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    • 2009
  • While late-life suicide has been increasing and become an important issue for public health in Korea, little is known about the phenomenon and its contributing risk factors based on which effective preventive measures can be made. Since suicidal ideation is a major precursor to attempted and completed suicide, the objective of the present study was to reveal primary contributors to suicidal ideation. Data were collected from a cross-sectional survey of 247 community-dwelling Korean older adults (age≥60) in the mid-size city in Korea. The statistical methodology employed a robust hierarchical regression procedure that iteratively downweights outliers. Based on the stress-diathesis model, the study examined major diathesis and stressors directly explaining suicidal ideation. The study also explored the significant interaction among these factors. The findings revealed that living alone and depression were significant main antecedents of suicidal ideation. In addition, neuroticism X life events and neuroticism X depression were significant interaction terms with the strongest explanatory power, which provides an empirical evidence to support the stress-diathesis model in explaining suicidal phenomenon of the Korean elderly. The result demonstrates the theoretical implication as well as the practical implication for developing and implementing late-life suicide prevention strategies. Limitations and directions for future research are discussed.

Mediating Effect of Professional Identity on the Relationship between Job- and Organization- related Factors and Job Satisfaction among Social Workers in Senior Welfare Facilities (노인생활시설 사회복지사들의 직무 및 조직특성과 직무만족도의 관계에서 전문직업적 정체성의 매개효과)

  • Cha, Myeong Jin;Je, Seok Bong
    • 한국노년학
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    • v.29 no.2
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    • pp.669-682
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    • 2009
  • The purpose of this study was to explore the role of professional identity as mediating variable in the relationship between job- and organization- related factors and job satisfaction. This study surveyed social workers who worked at 24 senior welfare facilities in Daegu·Gyeoungbuk province from Aug. 1. to Aug. 30. 2006. A total of 137 questionnaires were collected using on-site survey (response rate 76.7%). Statistical analyses were performed using SPSS 12.0 for Windows. Descriptive analysis and frequency analysis were performed on overall measurement items and hierarchical regression analysis was conducted to test the mediating effect of professional identity. The reliability of statements was acceptable since the coefficient alphas were > .70. Results of hierarchical regression showed that professional identity was verified as a partial mediator in the relationship between factors related with job and organization and job satisfaction. As the population ages, there will be an increasing need for professional social workers effectively to work with and help care for the elderly. This study highlighted that job- and organization- related factors, namely self-regulations and social supports, are significantly related with job satisfaction of social workers. Especially, such effect was more significantly apparent in high professional identity which is playing a partial mediator. This result implies that there is potential to change work environments of social workers ensuring a delegation of power and responsibility. Therefore, efforts should be made to improve the promotion system and connect social worker as servant with community through diverse service learning programs.