• The Korean Journal of Applied Statistics
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• v.29 no.5
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• pp.907-920
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• 2016

This study suggests an outlier detection algorithm that uses quantile autoregressive model in time series data, eventually applying it to actual stock manipulation cases by comparing its performance to existing methods. Studies on outlier detection have traditionally been conducted mostly in general data and those in time series data are insufficient. They have also been limited to a parametric model, which is not convenient as it is complicated with an analysis that takes a long time. Thus, we suggest a new algorithm of outlier detection in time series data and through various simulations, compare it to existing algorithms. Especially, the outlier detection algorithm in time series data can be useful in finding stock manipulation. If stock price which had a certain pattern goes out of flow and generates an outlier, it can be due to intentional intervention and manipulation. We examined how fast the model can detect stock manipulations by applying it to actual stock manipulation cases.

• Environmental and Resource Economics Review
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• v.24 no.1
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• pp.225-249
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• 2015

There are growing interests in the introduction of consumer's selective electricity tariff systems in order to enhance demand response in electricity market in Korea. Real time pricing (RTP) and Time of Use (TOU) are typical examples of demand response system through which electricity price is linked to real time demand. This paper adopts an agent-based model to analyze the effects of such demand system on the counsumers' electricity costs. The result shows that real time pricing system is effective to reduce electricity costs of consumers by providing more flexible tariff system, depending on each consumer's demand pattern. This finding could be used as a basis for supporting smart grid system in the presence of responsive demand environment.

• Environmental and Resource Economics Review
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• v.20 no.2
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• pp.229-254
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• 2011

In this paper, we decomposed Greenhouse-Gas emissions of Korea's manufacturing industry using LMDI (Log Mean Divisia Index) method. Changes in $CO_2$ emissions from 1991 to 2007 studied in 5 different factors, industrial production (production effect), industry production mix (structure effect), sectoral energy intensity (intensity effect), sectoral energy mix (energy-mix effect), and $CO_2$ emission factors (emission-factor effect). By results, the structure effect and intensity effect has a role of reducing GHG emissions and The role of structure effect was bigger than intensity effect. The energy mix effect increased GHG emissions and emission-factor effect decreased GHG emissions. By time series analysis, IMF regime affected the GHG emission pattern. the structure effect and intensity effect in that regime was getting worse. After 2000, in the high oil price period, the structure effect and intensity effect is getting better.

• Korean Journal of Community Nutrition
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• v.12 no.5
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• pp.534-544
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• 2007

This study was carried out to investigate the fast food consumption patterns classified by age in Busan. The survey was conducted from October 15 to November 15, 2006 by questionnaires and data analyzed by SPSS program. The results are summarized as follows: Forty one point five percent of the elementary group, 40.5% of the high school group, 24.1% of the 30's, 35.0% of the 40's and 18.1% of the 50's took fast foods over once a week. Seventy two point five percent of the elementary group, 61.5% of the high school group, 16.8% of the 30's group, 10.0% of the 40's, and 14.6% of the 50's preferred fast foods. There was a significant difference in the basis for selecting menus among the groups. The most important basis for selecting menus was 'price' in the elementary group and the high school group, but was 'preference' in the adult groups. As their age increased, they spend more money for fast food. Forty six percent of the elementary group and 49.5% of the high school group, 32.1% of the 30's, 36.5% of the 40's, 34.7% of the 50's thought that fast food can substitute for a meal. The age affected significantly the substitutability for the meal of the fast food (p < 0.001). In the high school group, the ratio of skipping breakfast is higher than in the other age groups. Dietary attitude has direct effects on the preference of the fast foods. Nutrition knowledge, degree of unbalanced diet and obesity rate have direct and indirect effects which were mediated by dietary attitude. Nutrition knowledge showed the greatest total causal effect in relation to the preference of the fast foods. Therefore, nutrition education for the subjects is needed to encourage them to choose more nutritious food and have healthier dietary pattern.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.1 s.149
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• pp.20-30
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• 2006

The purposes of this study were to investigate demographic profiles between the consumer group under high time pressure(HTP) and the group under low time pressure(LTP) during the shopping, to examine the level of association between the fashion information sources and time pressure variable, to determine the difference in clothing benefits sought between HTP and LTP, and to determine the difference in purchase criteria. We distributed questionnaires to 600 women aged in 20-65. The reliable 562 questionnaires were used for a statistical analysis. Data analyses were conducted with SPSS program on t-test, cluster analysis, factor analysis, and Chi square test. We obtained the following results: There was a significant association between demographic variables such as age, occupation, education, residence area, & family cycle and time pressure variable. Fashion information sources were classified into 4 factors. HTP searched information on fashion products using more various sources than LTP did. There was also a significant difference between HTP and LTP in clothing benefit sought. Four clothing benefit factors such as trendy/social position, economic value, protection/comfort, and makeup of body shape were sought more by HTP than by LTP. In addition, HTP considered significantly more purchase criteria such as color/pattern, comfort, quality, suitability, material, sewing finishing, coordination, price, brand, easy care, and country of origin than LTP.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.299-307
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• 2012

In this study, Kimchi usage was examined by nationwide consumers. 1,000 consumers between 20~60 years olds from 15 cities/province based on an administrative district participated in this questionnaire, which were one-on one interviews from September 23th to October 14th, 2009. 76.1% of the customers prepared Kimchi by them self, 26.9% customers received Kimchi from relatives and, 13.1% purchase Kimchi from the market. In addition, the rate of preparing Kimchi by themselves increased with age(p<0.05). 4~6 cabbage heads(34.5%) was the most preferred quantity for preparing Kimchi at a time, which was followed by more than 10 heads(25.2%) and 2~3 heads(22.9%). Chinese cabbage Kimchi was the most preferred type for purchase. 49.1% of customers purchased Kimchi at the supermarket and warehouse market and the origin of the ingredients, taste and-, price of Kimchi were considered important factors. The satisfactory scores of selling Kimchi were variety 3.60, taste 3.11, freshness of main ingredient 3.10, hygiene 2.86, -appropriate salt usage 2.99 and-, the origin of ingredients 2.94. There were significant difference between gender in taste and hygiene of selling Kimchi (p<0.05). In conclusion, to provide more appropriate Kimchi based on changes in Kimchi usage and consumption patterns at home and in the community, new types of Kimchi should be developed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.39-46
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• 2014

In this paper, to operate 2.4 GHz Inverted-L antenna with On-Board Broadband characteristics is proposed. The antenna was designed on the system board, the bandwidth by adjusting the reactance of the antenna that was formed common-mode and differential-mode on the antenna stubs has been improved. The system size is $80mm{\times}60mm$, the size of the antenna was limited to $30mm{\times}60mm$, the thickness of FR4 dielectric substrate is 0.8 mm, FR4 dielectric constant 4.4 is used. The experimental results, the bandwidth from 17.2 to 24.1 %, the gain is 3.01~4.71 dB, omni-directional radiation pattern characteristics were obtained. By a mobile terminal design applying the results of the paper, the handset's price competitiveness and production efficiency can be improved.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.3
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• pp.429-437
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• 2011

This study evaluated on the purchasing patterns for bakery products and the effects of brand image on consumers' purchasing power while living in the Seoul area. The questionnaires developed for this study were distributed to 400 males and females aged 20 and older. A total of 385 questionnaires were used for analysis (96.0%) and the statistical analysis, descriptive analysis, and $x^2$-test were completed using SPSS (version 14.0) software. When purchasing bakery products, 'taste' (59.7%) was most important followed by 'shape and size' (13.2%), 'ingredients' (11.7%), 'price' (7.5%), 'expiration date' (5.2%). 'origin of ingredients' (2.1%), and 'packaging' (0.5%). Subject showed significant differences in their purchase of bakery products based on characteristics including 'age' (p<0.05), 'occupation' (p<0.01), 'type of family' (p<0.01), and 'income' (p<0.1) The most influential factor in purchasing bakery products was 'material' (score=3.73), followed by 'name value' (score=3.56). Brand image of bakery had an effect on bakery products as 'present' (score=3.83), 'sanitation' (score=3.58). And, the most high respondent in basis of deciding brand image consumer's was 'clean and nice interior'(53.1%), followed by 'high quality ingredients and packaging'(23.7%).

• The Research Journal of the Costume Culture
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• v.17 no.2
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• pp.255-269
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• 2009

The purpose of this study was to understand the internet fashion shopping behavior of men in their 20s, and to develop the internet shopping website with situation-based clothing coordination services for male comsumer in their 20s. The study was implemented through a normative descriptive survey method using a questionnaire. The survey was conducted in April and May 2006, and the sample group consisted of 280 men in their 20s from Busan and the provinces of Gyeongnam and Gyeongbuk. The data was analyzed by following statistical methods: frequency analysis, one-way-ANOV A, and Scheffe's test. The results are as follow: first, regarding internet the usage trend of male consumers in their 20s, it was shown that they usually spent more than 15 minutes and less than 30 minutes for internet shopping the price range from their experiences of clothing purchases was relatively high for they bought jackets or suits was relatively high. Second, an analysis on men's pattern of clothing purchase showed that many respondents purchase single items such as shirts or pants online. Third, in terms of their experiences of online purchase of coordinated clothes, 69% said "none." Yet, they showed positive assessment to a question whether they are willing to purchase clothes by using a situation-based coordination service or a 1:1 online coordination services. Fourth, the relationship between consumers' reactions to online situation-based clothing coordination services and respondents' demographic characteristics showed statistically significant different results in terms of occupation.

• The Research Journal of the Costume Culture
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• v.16 no.3
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• pp.444-460
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• 2008

The purposes of this study were to investigate life style and various clothing purchasing behaviors of female consumers, and to analyze the differences of life style and clothing purchasing behaviors by 3 age groups(adolescence, middle age, and senescence). The subjects were 750 adult women aged from twenties to sixties who live in Daejeon and Chungnam province. The research method is a survey and research instruments consisted of life style questionnaire, clothing purchasing behaviors questionnaires, and demographic attribution. Data were analyzed by factor analysis, variance analysis, Duncan's multiple range test and $X^2$ test, using SPSS program. The research results are follows. First, 6 factors were emerged in life style(appearance-oriented, achieve-oriented, social life-oriented, economic- oriented, equality of sexes-oriented, and leisure- oriented). Second, 5 factors were emerged in shopping orientation(resonable shopping, conspicuous shopping, voluptuous shopping, devoted shopping, and convenient shopping). Third, clothing purchasing behaviors of adult women showed many differences by age groups. Adolescence women considered more criterion including design, price, and color or pattern, purchased their clothing by psychological reason such as fashion change, and used internet as important source of clothing, whereas senescence women purchased by physical reason such as body size change and functional trouble, used friend and sales person as important source of clothing, and purchased clothing at department store and old style market.