• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.2
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• pp.171-177
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• 2011

Accuracy and computing time are considerable issues in machine learning. In general, the computing time for data analysis is increased in proportion to the size of given data. So, we need a sampling approach to reduce the size of training data. But, the accuracy of constructed model is decreased by going down the data size simultaneously. To solve this problem, we propose a new statistical sampling method having similar performance to the total data. We suggest a rule to select optimal sampling techniques according to given data structure. This paper shows a sampling method for reducing computing time with keeping the most of accuracy using cluster sampling, stratified sampling, and systematic sampling. We verify improved performance of proposed method by accuracy and computing time between sample data and total data using objective machine learning data sets.

• The Korean Journal of Community Living Science
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• v.21 no.4
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• pp.619-631
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• 2010

The purpose of this study is to segment and examine urban farmers behavior by applying a two-step cluster analysis and multi-nominal logit model. The data were collected by a telephone survey with two-staged stratified random sampling in the cities around the country for the purpose of acquiring representative data. Respondents were asked to describe their awareness of urban agriculture, their agricultural activity, and sociodemographic characteristics. Among 2,000 cases, 381 cases(19.1%) which were of participants in urban agriculture were analysed in SPSS. From the findings, 27.3% of respondents had heard the word 'urban agriculture', and 25.5% of them regarded themselves as urban farmers. Four different clusters were derived from two-step clusters based on motive, place, companion, area and hours. They were 'Large scale hobby farming(cluster 1)', ‘Weekend farm/ hobby farming(cluster 2)', 'Land/ Self-supporting farming(cluster 3)', and 'Small scale hobby farming(cluster 4)'. The result of multinomial logistic regression showed that there were significant differences among these four segmented groups in terms of age, city size and housing type. In other words, there is quite a possibility that urbanites select different urban farming types according to their socio-demographic profiles. Therefore, the urbanite profiles can be used as the basis for promoting policy of several urban agriculture types. According to the result, policy directions for facilitating urban agriculture were presented.

• 한국노년학
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• v.28 no.4
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• pp.1265-1278
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• 2008

The purpose of this study was to study the Relationships between Sport for All Participation and Physical and Mental Function affecting the Elderly's Self-perceived Health. For accomplishing this purpose of this study, the 308 subjects were selected by the multi-stage stratified cluster sampling method from the Seoul, in the years of 2008. presently. Out of the 360 questionnaires responded to, only 308 were used for data analysis because 52 were responded to incompletely or incorrectly. The survey questionaries were used to collect data. The questionary for physical function state were developed and standardized by kung-hee chung(1993), yang-lae Kim(2005). And mental function state were divided two parts; self-perceived scale and depress scale. The questionary for self-perceived scale were based on MMSE-K(Mini Mental State Examination-Korea). The questionary for Depression were based on Depression Scale developed by Beck(1978), adapted in Korean and standardization by Lee Young-ho & Song Jong-yong(1991), regulated by Jo Gyu-whang(2004). From the analysis of this study, the following conclusions were obtained: First, according to the elderly people's participation in leisure sport activities, it partially affected physical and mental function state. Second, according to the degree of elderly people's participation in leisure sport activities, it partially affected physical and mental function state.

• Journal of Preventive Medicine and Public Health
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• v.22 no.1 s.25
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• pp.162-168
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• 1989

This study was conducted to analyse attitudes to a new health care system in a rural community. The specific purpose of this thesis was to classify attitudes to the patient referral system in Kangwha county, and to identify factors affecting the attitudes. Sampling was done by a multi-stage stratified cluster sampling method from the population. The data were collected in Kangwha county through a structured interview survey for two weeks in June, 1957. Attitudes to the patient referral system were classified into four types based upon answers to questions about awareness of the system, the recognition for the necessity of the system, and opinions on the improvement of the system. The four types of attitudes were active acceptance(10.2%), partial acceptance (27.2%), refusal(35.8%), and indifference(26.7%). The respondent's age, educational level, age of head of household, medical insurance fee, the number of ill family members, and the percentage of medical utilization by the family were the variables which affected the attitudes. The medical insurance fee, respondent's age, age of head of household, and the percentage of medical utilization by the family were the statistically significant discriminant factors of the four types of attitudes.

• Journal of Family Resource Management and Policy Review
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• v.4 no.1
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• pp.95-111
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• 2000

The family financial management is the important element which has a effect on the improvement of family economic well-being. Thus the study sets up human & material resources and requirement as an input factor, family financial management as an throughput factor, and economic well-being as an output factor, and then identifies if there are some relationships among them by using a systematic approach of family financial management. The questionaires were distributed to 600 employed wives by carrying out cluster sampling and disproportional stratified sampling. The 573 cases of them were used as the mean, ratio, Pearson’s Correration, ANOVA, factors analysis, and Stepwise Regression using the SAS/PC+. The major findings of the study are as follows: 1) A practical application of information as on input variable, appears the fator which has an important effect upon the throughput factor, that is, family financial management. The employed wives should manage a lot of resources in rapidly changing social-economic circustances. So it shows that not only they should take informations open to their daily life and then make practical use of them in managing their family finance, but also they must be capable of judging and accepting reasonable informations in order to gain and manage resources suitable to the characteristics of family finance and family members’need. 2) There was significant relationship between the employed wives’family financial management and family economic well-being, focused on the systematic theory of family financial management. This study provides for the information to develope the program for the employed wives’family financial planning and counseling.

• Journal of Families and Better Life
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• v.33 no.2
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• pp.35-51
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• 2015

The purpose of this study was to provide information for research about residents' opinion toward the physical environments of elderly facilities, through the analysis and investigation on the research methodology of foreign academic journal articles from 1990 to 2014. The study results were as follows: Firstly, purposive sampling was a large majority of both facilities and elderly residents. In quantitative studies, many researchers have conducted simple random, cluster, or stratified sampling. Diverse facilities in area, size, location, and etc. should be considered for participation. The qualifications for residents' participation should be considered as well, so that they all could have autonomy for study participation. Secondly, questionnaire and semi-structured guide were likely to be used in independent and resident care facilities. On the other hand in assisted living and long-term care facilities, open questions and visual material were used as well. A compatible scale should be developed so that elderly having variable functional level could participate independently in the study. Thirdly, in data collection process, compliance with research ethics and well trained interviewer's skill were important for residents' active responses and minimization of response errors. Enough research period of time and mixed study in data collection will decrease the response error.

• Journal of The Korean Association For Science Education
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• v.15 no.2
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• pp.194-200
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• 1995

The purpose of this study is to investigate the attitudes related to the science of elementary and middle school students. The instrument used for measuring attitudes was developed by Korea National University of Education. 1488 students were sampled by stratified cluster sampling method. The major findings of this study are as follows. 1.Elementary school students have significantly higher attitude scores than middle school students. 2.The value of Pearson's correlation coefficient among the sub-categories of science attitudes was 0.3773 - 0.6336, which was significant at the 0.001 level. 3.There was no statistically significant difference between grade and sex in middle school students. 4.There was statistically significant difference between grade and sex in elementary school students.

• Journal of the korean society of oceanography
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• v.32 no.1
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• pp.38-45
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• 1997

To find out the changes in vertical distribution patterns over the 24-h period, a key and the first step to tackle the problem of adaptive significance of diel vertical migration (DVM), vertically stratified time series samplings with multiple opening/closing plankton samplers were done in the East Sea of Korea (Sea of Japan). Sampling was done almost every 4 h for one day period following the same water parcel in Nov. 1995 and May 1996, respectively. Resultant patterns of vertical distribution showed that some species such as most abundant taxa Metridia pacifica and Scolecithyicella minor, both Copepoda, performed DVM even in the study area of strong thermal stratification. Their patterns of DVM such as distance scales and timing of movements were not the same each other, and they were separated from other taxa in the dendrogram obtained by the cluster analyses, Most minor taxa grouped in one, however, seemed not to do DVM in the study area of strong thermal stratification. They usually preferred the warmer surface layer where the foods were probably more abundant.

• The Korean Journal of Applied Statistics
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• v.8 no.2
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• pp.43-54
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• 1995

The fishery household economy survey is a sample survey which produce estimates on the fishery household economy and fishery management in Korea. We propose a sample design for this survey. This design is developed based on results of 1990 fishery census and Shi-Do is assumed to be subpopulation for Shi-Do estimates. Samples are selected by stratified two-stage cluster sampling in Shi-Do and income function is found for stratification. Fishery household income is estimated by a linear estimator.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.3 s.31
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• pp.197-206
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• 1989

This study was to investigate brand images of ladies wear and the effects of fashion advertisements, and to determine the difference of brand image preference and the effects of fashion advertising by clothing life style. 421 subjects were gathered through stratified sampling method and, for data analysis, frequency distribution, $x^2-test$, Cronbach'$\alpha$, ANOVA, Duncan's multiple Range test, Multiple Dimentional Scaling (M.D.S.), Factor analysis, Cluster analysis, were conducted. The results are as follows; 1. In image formation process, feminine as formal image, manish as casual image, were recognized. 2. Four factors were determined for analysis of clothing life styles and with these factors five different clothing life style groups were classified. 3. There was a meaningful difference between clothing life style and brand image preference, and also between clothing life style and the effects of fashion advertisement. From these findings, general and specific fashion advertising strategies are proposed.