• Journal of Korean Home Economics Education Association
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• v.24 no.2
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• pp.117-134
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• 2012

The purpose of this study was to identify the stage of concern, the level of use, and the innovation configuration of Home Economics teachers regarding creativity and personality education in Home Economics(HE) classes. The survey questionnaires were sent through mails and e-mails to middle-school HE teachers in the whole country selected by systematic sampling and convenience sampling. Questionnaires of the stages of concern and the levels of use developed by Hall(1987) were used in this study. 187 data were used for the final analysis by using SPSS/window(12.0) program. The results of the study were as following: First, for the stage of concerns of HE teachers on creativity and personality education, the information stage of concerns(85.51) was the one with the highest response rate and the next high in the following order: the management stage of concerns(81.88), the awareness stage of concerns(82.15), the refocusing stage of concerns(68.80), the collaboration stage of concerns(61.97), and the consequence stage of concerns(59.76). Second, the levels of use of HE teachers on creativity and personality education was highest with the mechanical levels(level 3; 21.4%) and the next high in the following order: the orientation levels of use(level 1; 20.9%), the refinement levels(level 5; 17.1%), the non-use levels(level 0; 15.0%), the preparation levels(level 2; 10.2%), the integration levels(level 6; 5.9%), the renewal levels(level 7; 4.8%), the routine levels(level 4; 4.8%). Third, for the innovation configuration of HE teachers on creativity and personality education, more than half of the HE teachers(56.1%) mainly focused on personality education in their HE classes; 31.0% of the HE teachers performed both creativity and personality education; a small number of teachers(6.4%) focused on creativity education; the same number of teachers(6.4%) responded that they do not focus on neither of the two. Examining the level and type of performance HE teachers applied, the average score on the performance of creativity and personality education was 3.76 out of 5.00 and the mean of creativity component was 3.59 and of personality component was 3.94, higher than standard. For the creativity education, openness/sensitivity(3.97) education was performed most and the next most in the following order: problem-solving skill(3.79), curiosity/interest(3.73), critical thinking(3.63), problem-finding skill(3.61), originality(3.57), analogy(3.47), fluency/adaptability(3.46), precision(3.46), imagination(3.37), and focus/sympathy(3.37). For the personality education, the following components were performed in order from most to least: power of execution(4.07), cooperation/consideration/just(4.06), self-management skill(4.04), civic consciousness(4.04), career development ability(4.03), environment adaptability(3.95), responsibility/ownership(3.94), decision making(3.89), trust/honesty/promise(3.88), autonomy(3.86), and global competency(3.55). Regarding what makes performing creativity and personality education difficult, most HE teachers(64.71%) chose the lack of instructional materials and 40.11% of participants chose the lack of seminar and workshop opportunity. 38.5% chose the difficulty of developing an evaluation criteria or an evaluation tool while 25.67% responded that they do not know any means of performing creativity and personality education. Regarding the better way to support for creativity and personality education, the HE teachers chose in order from most to least: 'expansion of hands-on activities for students related to education on creativity and personality'(4.34), 'development of HE classroom culture putting emphasis on creativity and personality'(4.29), 'a proper curriculum on creativity and personality education that goes along with students' developmental stages'(4.27), 'securing enough human resource and number of professors who will conduct creativity and personality education'(4.21), 'establishment of the concept and value of the education on creativity and personality'(4.09), and 'educational promotion on creativity and personality education supported by local communities and companies'(3.94).

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.694-708
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• 2009

The principal objective of this study was to determine the effects of smoking & drinking on the diet, nutrient intake, and overall health. A sample of 262 youths, aged 16 to 18 year-old, was randomly selected from Seoul and its vicinity. The subjects participated by answering survey questions including general questions, questions regarding health, smoking & drinking habits, dietary habits, nutrient intake, physical characteristics, and smoking cessation plans. The average height, weight, and BMI of the subjects were $173.5{\pm}6.8\;cm$, $64.8{\pm}11.8\;kg$, and $21.4{\pm}3.7\;kg/m^2$, respectively. Among the subjects, 88% appeared to be interested in health and 43.5% of youth asserted that the best way to keep healthy was to engage in regular exercise. Among 63 smokers, 52 students (82.5%) used alcoholic beverages while 11 students (17.5%) did not use alcoholic beverages, meaning that smoking was a causative factor in drinking. 55.6% of youth reported beginning to smoke in middle school, and 38.1% of them asserted that curiosity was the motive for smoking. The youth reported that the craving for smoking was highest when hungry, and the best place to smoke was the restroom. 20 students (69.0%) answered that the only way to quit smoking was just to stop. 12 students (44.4%) reported that the main reason for failures in smoking cessation attempts was a lack of intention or willpower. 87.1% of all subjects answered that they were inclined to quit smoking, and 56.7% of them would be interested in attending a smoking cessation program if they had the opportunity. Among the smoking and drinking group, 50% of drinkers began to drink in high school, and the reason for drinking given was peer pressure-40% of drinkers answered that they wished to quit drinking. 34.4% of students appeared to have breakfast everyday, but 16.4% of students answered that they had quit eating breakfast. 52.5% of all students reported that the principal reason for overeating was the presence of one's favorite food, and the smoking and drinking group reported overeating more frequently than other groups (p<0.05). 72.6% of all subjects reported eating interim meals $1{\sim}2$ times daily, 36.4% of smokers ate carbonated beverages, 38.5% ate ice cream as a interim meal, and 38.5% of the drinking and smoking groups ate fruits, 26.9% of them ate fried foods, and some of them ate fast foods as a interim meal. Among smokers, the ratio of eating fat-rich foods, and meats such as kalbi and samgyupsal more than two times per week was higher, and 54.3% of smokers ate ice cream, cookies, and carbonated beverages more than two times per week (p<0.05). The total nutrient intake of the $15{\sim}19$-year youth group was much higher than the standard value. The energy intake of the smoking group and the drinking and smoking group was significantly higher than that of the normal group (p<0.05). Intakes of phosphorus (p<0.05), cholesterol (p<0.05), and sodium (p<0.05) were the highest among all groups. Accordingly, it is recommended that practical education programs be implemented to teach young students to resist peer pressures to smoke and drink. Additionally, education that acknowledges the importance of nutrition is necessary to avoid preferential eating and overeating due to smoking and drinking.such education can also teach students to eat a balanced diet and improve their physical development.

• Journal of Intelligence and Information Systems
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• v.19 no.3
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• pp.1-23
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• 2013

To discover significant social issues such as unemployment, economy crisis, social welfare etc. that are urgent issues to be solved in a modern society, in the existing approach, researchers usually collect opinions from professional experts and scholars through either online or offline surveys. However, such a method does not seem to be effective from time to time. As usual, due to the problem of expense, a large number of survey replies are seldom gathered. In some cases, it is also hard to find out professional persons dealing with specific social issues. Thus, the sample set is often small and may have some bias. Furthermore, regarding a social issue, several experts may make totally different conclusions because each expert has his subjective point of view and different background. In this case, it is considerably hard to figure out what current social issues are and which social issues are really important. To surmount the shortcomings of the current approach, in this paper, we develop a prototype system that semi-automatically detects social issue keywords representing social issues and problems from about 1.3 million news articles issued by about 10 major domestic presses in Korea from June 2009 until July 2012. Our proposed system consists of (1) collecting and extracting texts from the collected news articles, (2) identifying only news articles related to social issues, (3) analyzing the lexical items of Korean sentences, (4) finding a set of topics regarding social keywords over time based on probabilistic topic modeling, (5) matching relevant paragraphs to a given topic, and (6) visualizing social keywords for easy understanding. In particular, we propose a novel matching algorithm relying on generative models. The goal of our proposed matching algorithm is to best match paragraphs to each topic. Technically, using a topic model such as Latent Dirichlet Allocation (LDA), we can obtain a set of topics, each of which has relevant terms and their probability values. In our problem, given a set of text documents (e.g., news articles), LDA shows a set of topic clusters, and then each topic cluster is labeled by human annotators, where each topic label stands for a social keyword. For example, suppose there is a topic (e.g., Topic1 = {(unemployment, 0.4), (layoff, 0.3), (business, 0.3)}) and then a human annotator labels "Unemployment Problem" on Topic1. In this example, it is non-trivial to understand what happened to the unemployment problem in our society. In other words, taking a look at only social keywords, we have no idea of the detailed events occurring in our society. To tackle this matter, we develop the matching algorithm that computes the probability value of a paragraph given a topic, relying on (i) topic terms and (ii) their probability values. For instance, given a set of text documents, we segment each text document to paragraphs. In the meantime, using LDA, we can extract a set of topics from the text documents. Based on our matching process, each paragraph is assigned to a topic, indicating that the paragraph best matches the topic. Finally, each topic has several best matched paragraphs. Furthermore, assuming there are a topic (e.g., Unemployment Problem) and the best matched paragraph (e.g., Up to 300 workers lost their jobs in XXX company at Seoul). In this case, we can grasp the detailed information of the social keyword such as "300 workers", "unemployment", "XXX company", and "Seoul". In addition, our system visualizes social keywords over time. Therefore, through our matching process and keyword visualization, most researchers will be able to detect social issues easily and quickly. Through this prototype system, we have detected various social issues appearing in our society and also showed effectiveness of our proposed methods according to our experimental results. Note that you can also use our proof-of-concept system in http://dslab.snu.ac.kr/demo.html.

• Journal of Intelligence and Information Systems
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• v.23 no.3
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• pp.155-175
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• 2017

As social data become into the spotlight, mainstream web search engines provide data indicate how many people searched specific keyword: Web Search Traffic data. Web search traffic information is collection of each crowd that search for specific keyword. In a various area, web search traffic can be used as one of useful variables that represent the attention of common users on specific interests. A lot of studies uses web search traffic data to nowcast or forecast social phenomenon such as epidemic prediction, consumer pattern analysis, product life cycle, financial invest modeling and so on. Also web search traffic data have begun to be applied to predict tourist inbound. Proper demand prediction is needed because tourism is high value-added industry as increasing employment and foreign exchange. Among those tourists, especially Chinese tourists: Youke is continuously growing nowadays, Youke has been largest tourist inbound of Korea tourism for many years and tourism profits per one Youke as well. It is important that research into proper demand prediction approaches of Youke in both public and private sector. Accurate tourism demands prediction is important to efficient decision making in a limited resource. This study suggests improved model that reflects latest issue of society by presented the attention from group of individual. Trip abroad is generally high-involvement activity so that potential tourists likely deep into searching for information about their own trip. Web search traffic data presents tourists' attention in the process of preparation their journey instantaneous and dynamic way. So that this study attempted select key words that potential Chinese tourists likely searched out internet. Baidu-Chinese biggest web search engine that share over 80%- provides users with accessing to web search traffic data. Qualitative interview with potential tourists helps us to understand the information search behavior before a trip and identify the keywords for this study. Selected key words of web search traffic are categorized by how much directly related to "Korean Tourism" in a three levels. Classifying categories helps to find out which keyword can explain Youke inbound demands from close one to far one as distance of category. Web search traffic data of each key words gathered by web crawler developed to crawling web search data onto Baidu Index. Using automatically gathered variable data, linear model is designed by multiple regression analysis for suitable for operational application of decision and policy making because of easiness to explanation about variables' effective relationship. After regression linear models have composed, comparing with model composed traditional variables and model additional input web search traffic data variables to traditional model has conducted by significance and R squared. after comparing performance of models, final model is composed. Final regression model has improved explanation and advantage of real-time immediacy and convenience than traditional model. Furthermore, this study demonstrates system intuitively visualized to general use -Youke Mining solution has several functions of tourist decision making including embed final regression model. Youke Mining solution has algorithm based on data science and well-designed simple interface. In the end this research suggests three significant meanings on theoretical, practical and political aspects. Theoretically, Youke Mining system and the model in this research are the first step on the Youke inbound prediction using interactive and instant variable: web search traffic information represents tourists' attention while prepare their trip. Baidu web search traffic data has more than 80% of web search engine market. Practically, Baidu data could represent attention of the potential tourists who prepare their own tour as real-time. Finally, in political way, designed Chinese tourist demands prediction model based on web search traffic can be used to tourism decision making for efficient managing of resource and optimizing opportunity for successful policy.

• Journal of Distribution Research
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• v.15 no.4
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• pp.1-19
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• 2010

As having the movement of developing private brand (PB) goods, domestic big retailers are facing up with new problems. Thus, it is required studies of PB products, and how consumers recognize PB products as a consideration commodity set. Also, it is worthy in order that it gives us the important meaning on the marketing strategy with focusing on evaluating the differences between customers buying PB grocery goods with respect to demographic characteristics and purchasing behaviors. PB has some advantages for customers and retailers. However, according to AC Nielson's report (2005), Asian and emerging market has 1/5 sales relatively to Western countries. But we can assume that the emerging market has the most potential growth through this result. As a result from several other studies, it becomes necessary to not only increase the rate of selling composition of PB product temporarily, but also analyze the characteristics of customers using big retailers and segmenting customer groups to make PB product as a consideration commodity set for them. In addition, it is needed to have a variety of acts of marketing. From studies related to PB, there is a prejudice - cheap products have low quality - but, evaluation by customers who have used those products shows neutral stand, and there is a study representing that it is the most important to accumulate the belief between the retailers selling PB products and consumers using those for the accurate evaluation and intention on purchasing. Also, by the result from analyzing the characteristics of customers buying PB products, we could assume that higher income and higher education level, more preference on PB products. Especially, according to TNS's research, the primary targets of PB product are 30's who seeks value for money and planned spending habits, and 40's who have teenager children, and are interested in encouraging themselves. This paper used Probit model to analyze the characteristics of consumers. This model helps us to analyze with the variables representing the demographic characteristics of consumers (gender, age, educational level, occupation, income level, living area), and variables related to purchasing behavior (visiting frequency on big retailers, the average amount that they pay for goods in there, and check-up which brand made those goods). The method we used in this study is by man to man interview and survey on-line with the rate of 89% and 11% in Seoul and Gyunggi Province, respectively, for about one month from the beginning of February, 2008. As a result of this, under the assumption that people buy PB products more as long as they go shopping more, it was not meaningful for target groups which we pointed out as frequently visiting customers to be. Although, we have expected women buy more PB products than men do, gender doesn't mean anything for the result. And, it has inferred that married people buy more PB goods than singles do. It was also meaningless with variables related to occupation. Because housewives are often exposed to any kind of supermarket than workers are, we could not get any relatives. Moreover, we couldn't proof that younger generation prefer big retailers more than older people who 50~60's. Education levels doesn't affect on the purchase of PB product as well. Related to living area, the result is statistically not similar as we expected whether living in Seoul or not. It shows there is no relationship with the preference on retail brands and PB products, and it is similar with the study researched by TNS(2008) that customers tend to buy PB product impulsively no matter which brand it is and where they are even though their shopping place is the big market where customers are often using. Variables on which we had meaningful results are income level and living place. That is, customers who have 3,000,000~6,000,000 WON every month on average are more willing to buy PB products than other customers whose income is over 6,000,000 WON, and residents not living in Seoul prefer PB goods than those who are living in Seoul. To explain more about what we got, if there is only one condition about customer's visiting frequency on big retails, we could come up with this result that more exposed to PB products, more purchasing frequency. Consequently, it brings the important insight that large retailers have to prepare something to make customers visit them often to increase selling rate of PB products. To demonstrate the result of analyzing more, what is more efficient variables are demographically including marital status, income level, and residential area to buy items that affect the PB products and could include the frequency of visiting large markets by the purchase habits. Specifically, then, married couples rather than singles, middle-income customers than high-income customers, and local residents not living in Seoul than customers in Seoul are more likely to purchase PB goods. In addition, as long as a customer visits two times more, then the purchasing rate of PB products is to increase over 5.3%. Therefore, it seems that retailers are better to make a shopping place as fun and comfortable places. With overwhelming the idea that PB products are just cheap, one-time purchase goods, it is needed to increase the loyalty on those goods like NB products, try to make PB products as a consideration products set, and occur to sustainable sales. Especially, as suggested by this paper, it seems like it strongly needs to identify the characteristics of customers who prefer PB, to segment those customers, and to select the main target, and to do positioning with well-planned marketing strategies. Then, it is able to give us a meaningful point on marketing strategy by developing the field of PB study, identifying the difference of life style and shopping habits of customers.

• (The) Research of the performance art and culture
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• no.18
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• pp.413-444
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• 2009

This paper is an analysis of stage and performance elements for the ceremonial procedures and dance featured in bongsudang-jinchan, a feast celebrating the 60th birthday of Hyegyeong-gung Hongssi (Crown Princess Hong of Hyegyeonggung), the mother of King Jeongjo, which took place in Hwaseong haegung palace in 1795. The primary sources used are data on bongsudangjinchan recorded in Wonhaeng-eulmyojeongriuigwe, Jeongjo-sillok, Hongjae-jeonseo, pictorial sources such as Folding Screens of Hwaseong-neunghaeng and Hwaseong Ilgi, which is a journal in Korean by Yi Hui-pyeong. A court ceremony to offer music, dance, flowers, and food, as well as wine and poetry which express the sentiments of chung (fidelity) and hyo (filial piety) was considered a national ceremony and has constituted a unique musical culture during the 500 years of Joseon dynasty. However, after the fall of Joseon dynasty, ceremonial music and dance, which have been organically linked within the overall symbolic system of ye (courtesy), became scattered to become independent 'pieces.' As a result, all of their philosophy, principles, and the time-space interpretation of court music and dance became greatly reduced, leaving only the artistic expression and formal structure of the music and dance to become emphasized. Since the 1990s, there has been many research and events aiming to re-create the court ceremonial tradition, resulting in the increase of the related performance activities. This is especially true with bongsudang-jinchan, which is now being performed on modern stage in various forms. However there are still many problems to be solved, such as the issue of re-creating and restoring the original, and the question of artistic value found in the traditional pieces. Until now, much focus has been paid to the outer re-construction of uiju document as recorded in Wonhaeng-eulmyo-jeongriuigwe. On the other hand, there lacked an in-depth study which analyzes the stage situation and performance elements. Therefore in this paper, after focusing on the stage structure and performance elements, it is concluded that bongsudang-jinchan, the only court feast to be held in Haeng gung, not only consists of the fundamental aspects of court performance principle as 'governing through ye and ak (music),' but also served as an important occasion to bring together the sovereign and the subject. Bongsudang-jinchan had features of both naeyeon (feast for ladies) and oeyeon (feast for gentlemen). It minimized the use of screens and allowed every guest to enjoy food, music, and dance together, but provided a separate tent for foreign guests, maintaining the ideal balance between equality and distinction among different gender and social status. A screen symbolizing the venue for the feast is placed for all of the government officials. The king then pronounces the beginning of the banquet in which the ideal of gunsin-dongyeon (king and officials dining together) is realized. This indicates that bongsudang-jinchan, compared to other court ceremonies that emphasize the principle of yeak (courtesy and music), focuses more on the spirit of harmony and rapprochement. The king played a more active role in bongsudang-jinchan than in any other royal feasts. Examples as recorded in uiju documents are; Jeongjo's conversation with his retainers after the 7th wine, king's bestowing of food and flowers to the officials, writing his own majesty's poems with regard to the festival, and asking the retainers to write replying poems. All these played an important part in making the occasion more rich, extensive, and meaningful. Moreover, as analysis of the structure of orchestral music and court dance featured in bongsudang-jinchan shows, it was like any other court banquet in that it employed minimal use of extravagance in movements and conversation. However, the colors and tonal texture used in the music and dance were more brilliant in this case. Compared to other banquets that took place before king Jeongjo, the dance style was more diverse, which included some of the latest additions. There were past performances arranged anew. Noteworthy are; the incorporation of "Seonyurak (Boat Dance)" and "Geommu (Sword Dance)," traditionally used for local officials and civilians feast, to suit the court taste; and the use of saenghwang (mouth organ), which was a rising instrument in pungnyubang (literati's private salon), for "Hakmu (Cranes Dance)." This especially indicates the nature of the 'open structure' pursued by the court banquets at the time, which strove to break away from the traditional rules and customs and accept something new.

• MISULJARYO - National Museum of Korea Art Journal
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• v.96
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• pp.155-180
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• 2019

Samsaebulhoedo(三世佛會圖) at Yongjusa Temple(龍珠寺), regarded as a monumental masterpiece consisting of different elements such as Confucian and Buddhist ideas, palace academy garden and Buddhist artist styles, unique traditional and western painting styles, is one of the representative works that symbolically illustrate the development and innovation of painting in the late Joseon dynasty. However, the absence of painting inscriptions raised persistent controversy over the past half century among researchers as to the matters of estimating its production period, identifying the original author and analyzing style characteristics. In the end, the work failed to gain recognitions commensurate with its historical significance and value. It is the particularly vital issue in that estimating the production period of the existing masterpiece is the beginning of all other discussions. However, this issue has caused the ensuing debates since all details are difficult to be interpreted to a concise form due to a number of different records on painters and mixture of traditional buddhist painting styles used by buddhist painters and innovative western styles used by ordinary painters. Contrary to other ordinary Buddhist paintings, this painting, Samsaebulhoedo, has a praying letter for the royal establishment at the center of the main altar. It should be noted that regarding this painting, its original version-His Royal Highness King, Her Majesty, His Royal Crown Prince主上殿下, 王妃殿下, 世子邸下-was erased and instead added Her Love Majesty慈宮邸下 in front of Her Majesty. This praying letter can be assumed as one of the significant and objective evidence for estimating its production period. The new argument of the late 19th century production focused on this praying letter, and proposed that King Sunjo was then the first-born son when Yongjusa Temple was built in 1790 and it was not until January 1, 1800 that he was ascended to the Crown Prince. In this light, the existing praying letter with the eulogistic title-Crown Prince世子-should be considered revised after his ascension to the throne. Styles and icons bore some resemblance to Samsaebulhoedo at Cheongryongsa Temple or Bongeunsa Temple portrayed by Buddhist painters in the late 19th century. Therefore, the remaining Samsaebulhoedo should be depicted by them in the same period as western styles were introduced in Buddhist painting in later days. Following extensive investigations, praying letters in Buddhist paintings in the late 19th century show that it was usual to record specification such as class, birth date and family name of people during the dynasty at the point of producing Buddhist paintings. It is easy to find that those who passed away decades ago cannot be revised to use eulogistic titles as seen by the praying letters in Samsaebulhoedo at Yongju Temple. As "His Royal Highness King, Her Majesty, His Royal Crown Prince" was generally used around 1790 regardless of the presence of first-born son or Crown Prince, it was rather natural to write the eulogistic title "His Royal Crown Prince" in the praying letter of Samsaebulhoedo. Contrary to ordinary royal hierarchy, Her Love Majesty was placed in front of Her Majesty. Based on this, the praying letter was assumed to be revised since King Jeongjo placed royal status of Hyegyeonggung before the Queen, which was an exceptional case during King Jeongjo's reign, due to unusual relationships among King Jeongjo, Hyegyeonggung and the Queen arising from the death of Crown Prince(思悼世子). At that time, there was a special case of originally writing a formal tripod praying letter, as can be seen from ordinary praying letter in Buddhist paintings, erasing it and adding a special eulogistic title: Her Love Majesty. This indicates that King Jeongjo identified that Hyegyeonggung was erased, and commanded to add it; nevertheless, ceremony leaders of Yongju Temple, built as a palace for holding ceremonies of Hyeonryungwon(顯隆園) are Jeongjo, the son of his father and his wife Hyegyeonggung (Her Love Majesty)(惠慶宮(慈宮)). This revision is believed to be ordered by King Jeongjo on January 17, 1791 when the King paid his first visit to the Hyeonryungwon since the establishment of Hyeonryungwon and Yongju Temple, stopped by Yongju Temple on his way to palace and saw Samsaebulhoedo for the first and last time. As shown above, this letter consisting of special contents and forms can be seen an obvious, objective testament to the original of Samsebulhoedo painted in 1790 when Yongju Temple was built.

• Asia Marketing Journal
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• v.14 no.1
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• pp.83-98
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• 2012

In a market where new and used cars are competing with each other, we would run the risk of obtaining biased estimates of cross elasticity between them if we focus on only new cars or on only used cars. Unfortunately, most of previous studies on the automobile industry have focused on only new car models without taking into account the effect of used cars' pricing policy on new cars' market shares and vice versa, resulting in inadequate prediction of reactive pricing in response to competitors' rebate or price discount. However, there are some exceptions. Purohit (1992) and Sullivan (1990) looked into both new and used car markets at the same time to examine the effect of new car model launching on the used car prices. But their studies have some limitations in that they employed the average used car prices reported in NADA Used Car Guide instead of actual transaction prices. Some of the conflicting results may be due to this problem in the data. Park (1998) recognized this problem and used the actual prices in his study. His work is notable in that he investigated the qualitative effect of new car model launching on the pricing policy of the used car in terms of reinforcement of brand equity. The current work also used the actual price like Park (1998) but the quantitative aspect of competitive price promotion between new and used cars of the same model was explored. In this study, I develop a model that assumes that the cross elasticity between new and used cars of the same model is higher than those amongst new cars and used cars of the different model. Specifically, I apply the nested logit model that assumes the car model choice at the first stage and the choice between new and used cars at the second stage. This proposed model is compared to the IIA (Independence of Irrelevant Alternatives) model that assumes that there is no decision hierarchy but that new and used cars of the different model are all substitutable at the first stage. The data for this study are drawn from Power Information Network (PIN), an affiliate of J.D. Power and Associates. PIN collects sales transaction data from a sample of dealerships in the major metropolitan areas in the U.S. These are retail transactions, i.e., sales or leases to final consumers, excluding fleet sales and including both new car and used car sales. Each observation in the PIN database contains the transaction date, the manufacturer, model year, make, model, trim and other car information, the transaction price, consumer rebates, the interest rate, term, amount financed (when the vehicle is financed or leased), etc. I used data for the compact cars sold during the period January 2009- June 2009. The new and used cars of the top nine selling models are included in the study: Mazda 3, Honda Civic, Chevrolet Cobalt, Toyota Corolla, Hyundai Elantra, Ford Focus, Volkswagen Jetta, Nissan Sentra, and Kia Spectra. These models in the study accounted for 87% of category unit sales. Empirical application of the nested logit model showed that the proposed model outperformed the IIA (Independence of Irrelevant Alternatives) model in both calibration and holdout samples. The other comparison model that assumes choice between new and used cars at the first stage and car model choice at the second stage turned out to be mis-specfied since the dissimilarity parameter (i.e., inclusive or categroy value parameter) was estimated to be greater than 1. Post hoc analysis based on estimated parameters was conducted employing the modified Lanczo's iterative method. This method is intuitively appealing. For example, suppose a new car offers a certain amount of rebate and gains market share at first. In response to this rebate, a used car of the same model keeps decreasing price until it regains the lost market share to maintain the status quo. The new car settle down to a lowered market share due to the used car's reaction. The method enables us to find the amount of price discount to main the status quo and equilibrium market shares of the new and used cars. In the first simulation, I used Jetta as a focal brand to see how its new and used cars set prices, rebates or APR interactively assuming that reactive cars respond to price promotion to maintain the status quo. The simulation results showed that the IIA model underestimates cross elasticities, resulting in suggesting less aggressive used car price discount in response to new cars' rebate than the proposed nested logit model. In the second simulation, I used Elantra to reconfirm the result for Jetta and came to the same conclusion. In the third simulation, I had Corolla offer $1,000 rebate to see what could be the best response for Elantra's new and used cars. Interestingly, Elantra's used car could maintain the status quo by offering lower price discount ($160) than the new car ($205). In the future research, we might want to explore the plausibility of the alternative nested logit model. For example, the NUB model that assumes choice between new and used cars at the first stage and brand choice at the second stage could be a possibility even though it was rejected in the current study because of mis-specification (A dissimilarity parameter turned out to be higher than 1). The NUB model may have been rejected due to true mis-specification or data structure transmitted from a typical car dealership. In a typical car dealership, both new and used cars of the same model are displayed. Because of this fact, the BNU model that assumes brand choice at the first stage and choice between new and used cars at the second stage may have been favored in the current study since customers first choose a dealership (brand) then choose between new and used cars given this market environment. However, suppose there are dealerships that carry both new and used cars of various models, then the NUB model might fit the data as well as the BNU model. Which model is a better description of the data is an empirical question. In addition, it would be interesting to test a probabilistic mixture model of the BNU and NUB on a new data set.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.500-518
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• 1996

Background : The solitary pulmonary nodule(SPN) presents a diagnostic dilemma to the physician and the patient. Many clinical characteristics(i.e. age, smoking history, prior history of malignancy) and radiological characteristics( i.e. size, calcification, growth rate, several findings of computed tomography) have been proposed to help to determine whether the SPN was benign or malignant. However, most of these diagnostic guidelines are based on the data collected before computed tomography(CT) has been introduced and lung cancer was not as common as these days. Moreover, it is not well established whether these guidelines from western populations could be applicable to Korean patients. Methods : We had a retrospective analysis of the case records and radiographic findings in 114 patients presenting with SPN from Jan. 1994 to Feb. 1995 in Seoul National University Hospital, a tertiary referral hospital. Results : We observed the following results ; (1) Out of 113 SPNs, the etiology was documented in 94 SP IS. There were 34 benign SP s and 60 malignant SPNs. Among which, 49 SPNs were primary lung cancers and the most common hi stologic type was adenocarcinoma. (2) The average age of patients with benign and malignant SPNs was $49.7{\pm}12.0$ and $58.1{\pm}10.0$ years, respectively( p=0.0004), and the malignant SPNs had a striking linear propensity to increase with age. (3) No significant difference in the hi story of smoking was noted between the patients with benign SPNs($13.0{\pm}17.6$ pack- year) and those with malignant SPNs($18.6{\pm}25.1$ pack-year) (p=0.2108). (4) 9 out of 10 patients with prior history of malignancy had malignant SPNs. 5 were new primary lung cancers with no relation to prior malignancy. (5) The average size of benign SPNs($3.01{\pm}1.20cm$) and malignant SPNs($2.98{\pm}0.97cm$) was not significantly different(p=0.8937). (6) The volume doubling time could be calculated in 22 SPNs. 9 SPNs had the volume doubling time longer than 400 days. Out of these, 6 were malignant SPNs. (7) The CT findings suggesting malignancy included the lobulated or spiculated border, air- bronchogram, pleural tail, and lymphadenopathy. In contrast, calcification, central low attenuation, cavity with even thickness, well-marginated border, and peri nodular micronodules were more suggestive for benign nodule. (8) The diagnostic yield of percutaneous needle aspiration and biopsy was 57.6%(19/33) of benign SPNs and 81.0%(47/58) of malignant SPNs. The diagnostic value of sputum analysis and bronchoscopic evaluations were relatively very low. (9) 42.3%(11/26) of SPNs of undetermined etiology preoperatively turned out to be malignant after surgical resection. Overall, 75.4%(46/61) of surgically resected SPNs were malignant. Conclusions : We conclude that the likelihood of malignant SPN correlates the age of patient, prior history of malignancy, some CT findings including lobulated or spiculated border, air-bronchogram, pleural tail and lymphadenopathy. However, the history of smoking, the size of the nodule, and the volume doubling time are not helpful to determent whether the SPN is benign or malignant, which have been regarded as valuable clinical parameters previously. We suggest that aggressive diagnostic approach including surgical resection is necessary in patient with SPNs.

• Tuberculosis and Respiratory Diseases
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• v.46 no.2
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• pp.215-228
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• 1999

Background: Sarcoidosis is a chronic granulomatous inflammatory disease of unknown etiology often involving the lungs and intrathoracic lymph nodes. The natural course of sarcoidosis is variable from spontaneous remission to significant morbidity or death. But, the mechanisms causing the variable clinical outcomes or any single parameter to predict the prognosis was not known. In sarcoidosis, the number and the activity of CD4 + lymphocytes are significantly increased at the loci of disease and their oligoclonality suggests that the CD4 + lymphocytes hyperreactivity may be caused by persistent antigenic stimulus. Recently, it has been known that CD4+ lymphocytes can be subdivided into 2 distinct population(Th1 and Th2) defined by the spectrum of cytokines produced by these cells. Th1 cells promote cellular immunity associated with delayed type hypersensitivity reactions by generating IL-2 and IFN-$\gamma$. Th2 cells playa role in allergic responses and immediate hypersensitivity reactions by secreting IL-4, IL-5, and IL-10. CD4+ lymphocytes in pulmonary sarcoidosis were reported to be mainly Th1 cells. IL-12 has been known to play an important role in differentiation of undifferentiated naive T cells to Th1 cells. And, Moller et al. observed increased IL-12 in bronchoalveolar lavage fluid(BALF) in patients with sarcoidosis. So it is possible that the elevated level of IL-12 is necessary for the continuous progression of the disease in active sarcoidosis. This study was performed to test the assumption that IL-12 can be a marker of active pulmonary sarcoidosis. Methods: We measured the concentration of IL-12 in BALF and in conditioned medium of alveolar macrophage(AM) using ELISA(enzyme-linked immunosorbent assay) method in 26 patients with pulmonary sarcoidosis(10 males, 16 females, mean age: $39.8{\pm}2.1$ years) and 11 normal control. Clinically, 14 patients had active sarcoidosis and 12 patients had inactive. Results: Total cells counts, percentage and number of lymhocytes, number of AM and CD4/CD8 lymphocyte ratio in BALF were significantly higher in patients with sarcoidosis than in control group. But none of these parameters could differentiate active sarcoidosis from inactive disease. The concentration of IL-12 in BALF was significantly increased in sarcoidosis patients ($49.3{\pm}9.2$ pg/ml) than in normal control ($2.5{\pm}0.4$ pg/ml) (p<0.001). Moreover it was significantly higher in patients with active sarcoidosis ($70.3{\pm}14.8$ pg/ml) than in inactive disease ($24.8{\pm}3.l$ pg/ml) (p=0.001). Also, the concentration of IL-12 in BALF showed significant correlation with the percentage of AM(p<0.001), percentage(p<0.001) and number of lymphocyte(p<0.001) in BALF, suggesting the close relationship between the level of IL-12 in BALF and the inflammatory cell infiltration in the lungs. Furthermore, we found a significant correlation between the level of IL-12 and the concentration of soluble ICAM-1 : in serum(p<0.001) and BALF (p=0.001), and also between IL-12 level and ICAM-1 expression of AM(p<0.001). The AM from patients with pulmonary sarcoidosis secreted significantly larger amount of IL-12 ($206.2{\pm}61.9$ pg/ml) than those of control ($68.3{\pm}43.7$ pg/ml) (p<0.008), but, there was no difference between inactive and active disease group. Conclusion : Our data suggest that the BALF IL-12 level can be used as a marker of the activity of pulmonary sarcoidosis.