정규 모집단의 모평균 차이 검정에서 표본크기와 검정력 계산의 구현

심송용,최규혁,Sim, Songyong,Choi, Kyuhyeok 한국데이터정보과학회 2013 한국데이터정보과학회지 Vol.24 No.3

In this paper, we consider the sample sizes required for each group in independent two sample test of normal populations when both the type I error and type II error probabilities are specified with sample sizes and variances being possibly different. We derived the sample sizes and the power of the tests, and implement them by web programing. The result is available over the world wide web. Further, we also provide the power calculations and have them available on the web.

연속형의 텐서곱과 범주형의 직합을 사용한 다항 로지스틱 회귀모형

심송용,강희모,Sim, Songyong,Kang, Heemo 한국데이터정보과학회 2014 한국데이터정보과학회지 Vol.25 No.1

In this paper, we propose a polychotomous regression model when independent variables include both categorical and numerical variables. For categorical independent variables, we use direct sums, and tensor product splines are used for continuous independent variables. We use BIC for varible selections criterior. We implemented the algorithm and apply the algorithm to real data. The use of direct sums and tensor products outperformed the usual multinomial logistic regression model.

Implementation of Estimation and Inference on the Web

Kang, Heemo,Sim, Songyong 한국통계학회 2000 Communications for statistical applications and me Vol.7 No.3

An electronic statistics text on the web is implemented. The introduced text provide interactive instructions on the statistical estimation and inference. As a by-product, we also provide a calculation of quantiles and p-value of t-distribution and standard normal distribution. This program was written in JAVA programming language.

Regression and Correlation Analysis via Dynamic Graphs

Kang, Hee Mo,Sim, Songyong 한국통계학회 2003 Communications for statistical applications and me Vol.10 No.3

In this article, we propose a regression and correlation analysis via dynamic graphs and implement them in Java Web Start. For the polynomial relations between dependent and independent variables, dynamic graphics are implemented for both polynomial regression and spline estimates for an instant model selection. The results include basic statistics. They are available both as a web-based service and an application.

Development of a Tool to Measure the Need for Child Hospice Care in Families of Children with Cancer

( Kyung-ah Kang ),( Songyong Sim ),( Shin-jeong Kim ) 한국간호과학회 2005 한국간호과학회 학술대회 Vol.2005 No.-

High Incidence of Bell’s Palsy After Mastoidectomy: A Longitudinal Follow-up Study

Choi, Hyo Geun,Sim, Songyong,Hong, Sung Kwang,Park, Su-kyoung,Lee, Hyo-Jeong,Chang, Jiwon Lippincott Williams Wilkins 2017 Otology & Neurotology Vol.38 No.10

OBJECTIVE:: The objective of this study was to compare the prevalence of Bell’s palsy in participants who underwent mastoidectomy (to treat chronic otitis media) and nonmastoidectomy participants (control). METHODS:: Using the national cohort study from the Korean Health Insurance Review and Assessment Service, mastoidectomy patients (2,045) and control participants (8,180) were matched 1:4 for age, sex, income, and region of residence. The prevalence of Bell’s palsy in both the groups was measured from 0 to 10 years postoperation. RESULTS:: In a sample of 1,025,340 Korean individuals, 7,070 were diagnosed or treated with Bell’s palsy between 2002 and 2013; the annual incidence of Bell’s palsy was 0.057%. The overall prevalence of Bell’s palsy was three times higher in the mastoidectomy group (1.27%) than control group (0.49%) (p < 0.001). The prevalence of Bell’s palsy was different between the two groups in postoperative 0 year: 0.78% for the mastoidectomy group versus 0.01% for the control group (p < 0.001). CONCLUSION:: Although we could not verify the laterality, the prevalence of Bell’s palsy was increased in chronic otitis media patients treated with mastoidectomy patients compared with controls, especially within a year after surgery.

A Study on Data Mining Using the Spline Basis

Lee, Sun-Geune,Sim, Songyong,Koo, Ja-Yong 한국통계학회 2004 Communications for statistical applications and me Vol.11 No.2

Due to a computerized data processing, there are many cases when we encounter a huge data set. On the other hand, advances in computing technologies make it possible to deal with a huge data set. One important area is the data mining. In this paper we consider data mining when the dependent variable is binary. The proposed method is to use the poly-class model when the independent variables consists of continuous and discrete variables. An example is provided.

Dietary Habits Are Associated With School Performance in Adolescents

Kim, So Young,Sim, Songyong,Park, Bumjung,Kong, Il Gyu,Kim, Jin-Hwan,Choi, Hyo Geun Williams & Wilkins Co 2016 Medicine Vol.95 No.12

<P><B>Abstract</B></P><P>Several studies suggest that dietary habits are associated with poor academic performance. However, few studies have evaluated these relations after adjusting for numerous confounding factors. This study evaluated the frequency of various diet items (fruit, soft drinks, fast foods, instant noodles, confections, vegetables, and milk) and the regularity of meal times (breakfast, lunch, and dinner) all at once.</P><P>A total of 359,264 participants aged from 12 to 18 years old were pooled from the Korea Youth Risk Behavior Web-based Survey (KYRBWS) for the 2009 to 2013 period. Dietary habits over the last 7 days were surveyed, including the regularity of consuming breakfast, lunch and dinner and the frequency of eating fruits, soft drinks, fast foods, instant noodles, confections, vegetables, and milk. Physical activity, obesity, region of residence, subjective assessment of health, stress level, economic level, and parental education level were collected from all of the study participants. School performance was classified into 5 levels. The adjusted odds ratios (AORs) of dietary habits for school performance were analyzed using multinomial logistic regression analyses with complex sampling. Structural equation modeling was used to analyze the effects of diet factors on school performance while considering the effects of other variables on both diet factors and school performance.</P><P>Frequent intakes of breakfast (AOR = 2.34, 95% confidence interval [CI] = 2.20–2.48), fruits (AOR = 1.73, 95% CI = 1.62–1.86), vegetables (AOR = 1.48, 95% CI = 1.37–1.61), and milk (AOR = 1.35, 95% CI = 1.28–1.43) were related to high levels of school performance (each with <I>P</I> < 0.001). In contrast, soft drinks (AOR = 0.42, 95% CI = 0.38–0.46), instant noodles (AOR = 0.62, 95% CI = 0.55–0.70), fast food (AOR = 0.83, 95% CI = 0.72–0.96), and confectionary (AOR = 0.86, 95% CI = 0.80–0.93) were negatively associated with school performance (each with <I>P</I> < 0.001).</P><P>This study confirms previous studies of school performance and dietary habits that find a positive association with eating breakfast and consuming fruits and milk and a negative relation with soft drinks, instant noodles, fast foods, and confections.</P>

Increased risk of migraine in patients with psoriasis : A longitudinal follow up study using a national sample cohort

Min, Chanyang,Lim, Hyoseob,Lim, Jae-Sung,Sim, Songyong,Choi, Hyo Geun Williams & Wilkins Co 2019 Medicine Vol.98 No.17

A study on the classfication of households in Rwanda based on factor scores

Pacifique Nizeyimana,Kee-Won Lee,Songyong Sim 한국데이터정보과학회 2018 한국데이터정보과학회지 Vol.29 No.2

Many researchers have focused on grouping or classifying households into different categories based on either income/consumption or household assets. However, these practices may lead to an inadequate classification due to Rwanda"s unique family structure. In Rwanda, households are classified into six socio-economic classes known as `Ubudehe categories". This classification is based on subjective perceptions of people. In this study, we propose to use household assets as well as income/consumption to classify Rwandan households into different socio-economic categories. These approaches are summated Likert scale method and factor score method. When these two methods are compared by a discriminant analysis, the factor score method brings out more reliable results than Likert method.