• The Korean Journal of Applied Statistics
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• v.28 no.5
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• pp.965-976
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• 2015

Determining relevant variables for a regression model is important in regression analysis. Recently, a variable selection methods using a penalized likelihood with various penalty functions (e.g. LASSO and SCAD) have been widely studied in simple statistical models such as linear models and generalized linear models. The advantage of these methods is that they select important variables and estimate regression coefficients, simultaneously; therefore, they delete insignificant variables by estimating their coefficients as zero. We study how to select proper variables based on penalized hierarchical likelihood (HL) in semi-parametric frailty models that allow three penalty functions, LASSO, SCAD and HL. For the variable selection we develop a new function in the "frailtyHL" R package. Our methods are illustrated with breast cancer survival data from the Medical Center at Chonnam National University in Korea. We compare the results from three variable-selection methods and discuss advantages and disadvantages.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.416-416
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• 2019

육상 담수는 대기중 이산화탄소($CO_2$) 배출의 중요한 발생원으로 주목되고 있다. 하천 및 강에서 대기중으로 배출되는 $CO_2$는 전 세계 탄소순환의 핵심요소이며, 대부분의 하천과 강은 $CO_2$로 과포화 되어있다. 세계적으로 하천 및 강의 $CO_2$ 배출량은 호수 및 저수지의 배출량보다 약 5배 많은 것으로 보고되고 있으나, 국내연구에서는 연구사례가 드물다. 따라서 본 연구의 목적은 낙동강 중하류에 위치해있는 강정고령보(GGW), 달성보(DSW), 합천창녕보(HCW), 창녕함안보(CHW)에서 발생되는 순 대기 배출 플럭스(Net Atmospheric Flux, NAF)의 동적 변동 특성을 분석하고, 데이터마이닝 기법을 적용하여 쉽게 수집할 수 있는 물리적 및 수질 변수로 $CO_2$ NAF를 추정하는데 사용할 수 있는 간략한 예측 모델을 개발하는데 있다. $CO_2$ NAF는 대기-수면 경계면에서의 $CO_2$ 부분압($pCO_2$)의 차에 기체전달속도를 곱하여 산정하였으며, 기체전달속도는 Cole and Caraco(1998)가 제안한 식을 사용하였다. 담수와 해수의 탄산염 시스템에서 열역학적 화학평형을 모두 고려한 $CO_2$SYS 프로그램을 사용하여 수중의 $pCO_2$를 산정하였고, $CO_2$ NAF는 Henry의 법칙과 Fick의 1차 확산법칙을 사용하여 계산하였다. $CO_2$ NAF의 시간적 변동성에 영향을 미치는 환경요인을 평가하기 위해서 상관분석, 주성분분석(Principal Component Analysis; PCA), 단계적다중회귀모델(Step-wise Multiple Linear Regression; SMLR), 랜덤포레스트(Random Forest; RF)방법을 사용하였다. SMLR 모델은 R package인 olsrr, RF 모델은 R package인 caret, randomForest를 이용하여 분석하였다. 연구 결과, 4개 보 상류 하천구간은 조류의 성장이 활발한 일부 기간을 제외한 대부분의 기간에서 $CO_2$를 대기로 배출하는 종속영양시스템(Heterotrophic system)을 보였다. $CO_2$ NAF의 중위값은 HCW에서 최소 $391.5mg-CO_2/m^2day$, DSW에서 최대 $1472.7mg-CO_2/m^2day$였다. 모든 보에서 NAF는 pH와 강한 음의 상관관계를 보였으며, $pCO_2$와 Chl-a도 음의 상관관계를 보였다. 이는 조류가 수중에서 $CO_2$를 소비하고 pH를 증가시키기 때문이다. PCA 분석 결과, NAF와 $pCO_2$가 높은 공분산을 보였으며, pH와 Chl-a는 반대 방향으로 군집되어 상관분석과 동일한 결과를 보였다. 이 연구를 통해 개발된 SMLR 모델과 RF 모델의 Adj. $R^2$ 값은 모든 보에서 0.77 이상으로 나왔으며, $pCO_2$ 측정 데이터가 없더라도 하천의 $CO_2$ NAF를 추정하는 방법으로 사용될 수 있을 것으로 평가된다.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.1
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• pp.45-56
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• 2002

Objectives: Recently, recombinant FSH (rFSH) has been manufactured using a Chinese hamster ovary cell line transfected with the gene encoding human FSH. Both rFSH and urinary gonadotropin (uFSH) could be used for controlled ovarian hyperstimulation (COH). However, uFSH implies a number of disadvantages, such as batch-to-batch inconsistency, no absolute source control, dependence on large amounts of urine, low specific activity, and low purity. The purpose of this study was to evaluate the efficacy of rFSH in human IVF-ET program. Materials and Methods: A total of 508 infertile women was enrolled in this study. They are classified into rFSH group (n=177) or uFSH group (n=331), and all of them were matched by age and cause of infertility in same period. The $Puregon^{(R)}$ (Organon, Holland) was used as rFSH, and the Metrodin-$HP^{(R)}$ (Serono, Switzeland) and $Humegon^{(R)}$ (Organon, Holland) was used as uFSH. We subdivided the patients into three age groups. The outcomes of IVF-ET program were analyzed using the statistical package for social sciences (SPSS). Results: There was no significant differences in the level of estradiol on hCG injection day, the numbers of retrieved oocytes, matured oocytes, fertilized oocytes, transferred embryos, frozen embryos between the two groups. The total dose (IU) of gonadotropin for COH was significantly lower in the rFSH group compared to uFSH group ($1339{\pm}5491.1$ vs $2527.8{\pm}1075.2$ IU, p<0.001). Clinical pregnancy rate per embryo transfer in the rFSH group showed increasing tendency, compared to the uFSH group, but there was no statistical significance (35.2% vs 29.3%). Our results demonstrated that the relative efficiency of rFSH compared with uFSH is higher in older patients. Conclusions: The ovarian stimulatory effect and clinical outcome of recombinant FSH was similar to that of the urinary gonadotropin. The IVF-ET cycles with significantly lower dose of gonadotropin in rFSH group showed comparable results. Therefore, we suggest that recombinant FSH is more potent and effective than urinary gonadotropin.

• Journal of Korean Public Health Nursing
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• v.15 no.1
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• pp.42-55
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• 2001

The purpose of this study was to provide basic information for developing effective marketing strategies of nursing organization by identifying the correlation among internal marketing factor, nurses' job satisfaction, and organizational commitment. The subjects of this study were 256 nurses who were working in the hospital over 1 year at three university hospitals which had more than 400 beds in seoul and kyung-gido. The data were collected by self-reporting questionnaires. The instruments used in this study were the communication form scale developed by Jo(1995), the welfare scale developed by researcher, the education training scale developed by researcher, the organizational commitment scale developed by Mowday, Porter and Steers(1979). The data were analysed by the SAS package using frequency, percentage, mean, standard deviation, and Pearson's correlation coefficient. The results of this study were as follows; 1. Mean scores of internal marketing factors in nursing organization were as follows; horizontal communication 3.42, downward communication 3.32, involvement communication 3.08, upward communication 3.00, education training 2.54, welfare 2.51. The mean score of job satisfaction was 2.79 and organizational commitment was 3.00. 2. Job satisfaction was positively correlated with education training (r=0.54, p=0.0001), upward communication(r=0.49, p=0.0001). welfare (r=0.40, p=0.0001), horizontal communication(r=0.33, p=0.0001), involvement communication(r=0.25, p=0.0001) of internal marketing factors in nursing organization, but negatively correlated with downward communication(r=-0.16. p=0.0082). Organizational commitment was positively correlated with upward communication(r=0.48, p=0.0001), education training (r=0.42, p=0.0001), horizontal communication(r=0.36, p=0.0001), welfare (r=0.34, p=0.0001), involvement communication(r=0.25, p=0.0001) of internal marketing factors in nursing organization. but negatively correlated with downward communication(r=-0.20, p=0.0014). In conclusion. the results of this study showed that the internal marketing factors were highly correlated with nurses' job satisfaction and organizational commitment. Therefore, for nurses' job satisfaction and organizational commitment's improvement, it is important to develop the education training program. to improve welfare system and to actualize upward communication. among internal marketing factors.

• The Korean Journal of Franchise Management
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• v.2 no.2
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• pp.45-69
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• 2011

A basic function of packaging is preservability, delivery, subdivision, aesthetic and serviceability on packaging. Originally, the function and necessity of packaging is on preservability, but today it is expending before. then packaging is focusing on sales promotion. Although it is hard to say production itself, it could does when it is made. also, it is important for product to be goods when packaging and its materials are identification on matching each other. The role of packaging design is a core factor that satisfy consumer a various of needs and wants. In the past, the role of food packaging design is just preservability and delivery on product. but then, nawaday it is asked a various role. Not only present products have to get inherency but also have added value. That is, advanced technologies, information, and richness from materials which are diversity for coming a extention of choice. currently, food packaging design shouldn't have stayed on just packaging which cover beautiful. Packaging design is a symbolic sign. It is importance for manager to do R&D, producing, and distribution, also for consumer who use and buy the product whether manager and consumer think package design is a main mediation. This day, food design pay attention to be asking consumer's a number of sensitivity. It is the reason that the package is importance and exist. This article is to examine preservability, delivery, subdivision, aesthetic, serviceability, and environmental orientation in order to develop and show a method and theories to find package design in food industry the reason that why sales promotion and its profit increase. Consequently, draw on the function of package design effects the benefit on product is distribution. Green Design on the food packages by combining recycled and biodegradable food packages for the development of practices and long life to the look of the food package design practices.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.223-234
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• 2020

This research is the association rule analysis using Apriori algorithm of data mining focusing on 32 predictive key words extracted from Hong (2019) affecting successful aging in Korea. And, to examine rules and patterns of those key words or predictive variables, this research used support, confidence, and lift. The data was analyzed with the R version 3. 5. 1 program, and visualized using arulesViz package and visNetwork. It was found that the variables highly associated with successful aging in Korea were 'hobby', 'volunteer service', 'preparation', and 'exercise'. This research concludes that, the variable which needs to be considered first of all for successful aging in Korea is 'hobby', followed by 'volunteer service', 'preparation', and 'exercise'.

• Journal of Korean Academy of Nursing Administration
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• v.7 no.3
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• pp.487-495
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• 2001

Purpose : In this study, task performance and job satisfaction of nurses in non-life insurance companies were examined to improve the personnel management in their companies. Method : Data collection was done with 119 nurses in non-life insurance companies in October and November, 1999. Data analyses were performed using SPSS Win 8.0 package. Result: The Results were as follows: 1. The tasks most commonly performed by nurses were 'medical fee inspection', 'education for staves', 'management of the injured', 'management of injury and disablement'. 2. The mean score of total job satisfaction was 3.2(interaction. 3.8; professional status, 3.6; autonomy, 3.4; task requirements, 3.1; administration, 2.8; pay and advancement, 2.6). 3. Task performance was significantly correlated with job satisfaction total score(r=0.478, p<.01). The item, 'executing statistical works and data analyses related with injury and disablement', was highly correlated with job satisfaction total score(r=0.418, p<.01). 4. The amount of task performance was significantly correlated with educational background and position. The job satisfaction level significantly correlated with personal experience and position. Conclusion : To improve the work efficiency and job satisfaction in the companies, it is necessary to set the bounds of task performance and to enlarge the promotion opportunities to higher positions.

• Journal of Biosystems Engineering
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• v.34 no.5
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• pp.331-341
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• 2009

A double-end rod hydraulic cylinder is widely used with a steering valve for the steering control system in large tractors. For the development of automatic steering controller, the feasibility of using a proportional control valve replacing the conventional manual steering valve to control the position of hydraulic steering cylinder was investigated in terms of the max. overshoot, the steady-state error and the rise time. A simulation model for the electrohydraulic steering system with load using AMESim package was developed to be valid so that the proper control algorithm could be chosen through the computer simulation. It could be concluded that the P-control algorithm was sufficient to control the electrohydraulic steering system, where the control frequency should be no greater than 20 Hz at the P-gain of 5. In particular, the performance of the developed steering controller was satisfactory even at the conditions of varying flow rates and loads.

• The Korean Journal of Emergency Medical Services
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• v.24 no.1
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• pp.85-92
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• 2020

Purpose: The purpose of this study was to analyze the English abstract key words found within the Korea Society of Emergency Medical Services journal using text mining techniques to determine the adherence of these terms with Medical Subject Headings (MeSH) and identify key word trends. Methods: We analyzed 212 papers that were published from 2012 to 2019. R software, web scraping, and frequency analysis of key words were conducted using R's basic and text mining packages. Additionally, the Word Clouds package was used for visualization. Results: The average number of key words used per study was 3.9. Word cloud visualization revealed that CPR was most prominent in the first half and emergency medical technician was most frequently used during the second half. There were a total of 542 (64.9%) words that exactly matched the MeSH listed words. A total of 293 (35%) key words did not match MeSH listed words. Conclusion: Researchers should obey submission rules. Further, journals should update their respective submission rules. MeSH key words that are frequently cited should be suggested for use.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.38-46
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• 2010

For the development of 100[W] stage lighting, quantitative and uniform color mixing that applied through color adopted Simple-Inverse matching so that color mixing can be possible along Black Body Locus. R,G,B(Red, Green, Blue) LED(Light Emitting Diode) arrangement through LED package character analysis, LED module, and the characteristic of device were considered for uniform color mixing. A distance changeable optical device was built to assure high uniformity and high diffusion of not only the middle of diffusion side but also the border side. Also, we developed the control power circuit that can expand up to 6 channels which are possible for quantitative color mixing, and the high uniformity and high quantified border light for color mixing control and the verification of color mixing characteristics by composing GUI(Graphical user interface) including color mixing simulator. By presenting the experimental results of light color control, we proved the usefulness of our developed border light and the proposed color mixing method.