• Journal of Intelligence and Information Systems
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• v.19 no.2
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• pp.125-140
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• 2013

We call a data set in which the number of records belonging to a certain class far outnumbers the number of records belonging to the other class, 'imbalanced data set'. Most of the classification techniques perform poorly on imbalanced data sets. When we evaluate the performance of a certain classification technique, we need to measure not only 'accuracy' but also 'sensitivity' and 'specificity'. In a customer churn prediction problem, 'retention' records account for the majority class, and 'churn' records account for the minority class. Sensitivity measures the proportion of actual retentions which are correctly identified as such. Specificity measures the proportion of churns which are correctly identified as such. The poor performance of the classification techniques on imbalanced data sets is due to the low value of specificity. Many previous researches on imbalanced data sets employed 'oversampling' technique where members of the minority class are sampled more than those of the majority class in order to make a relatively balanced data set. When a classification model is constructed using this oversampled balanced data set, specificity can be improved but sensitivity will be decreased. In this research, we developed a hybrid model of support vector machine (SVM), artificial neural network (ANN) and decision tree, that improves specificity while maintaining sensitivity. We named this hybrid model 'hybrid SVM model.' The process of construction and prediction of our hybrid SVM model is as follows. By oversampling from the original imbalanced data set, a balanced data set is prepared. SVM_I model and ANN_I model are constructed using the imbalanced data set, and SVM_B model is constructed using the balanced data set. SVM_I model is superior in sensitivity and SVM_B model is superior in specificity. For a record on which both SVM_I model and SVM_B model make the same prediction, that prediction becomes the final solution. If they make different prediction, the final solution is determined by the discrimination rules obtained by ANN and decision tree. For a record on which SVM_I model and SVM_B model make different predictions, a decision tree model is constructed using ANN_I output value as input and actual retention or churn as target. We obtained the following two discrimination rules: 'IF ANN_I output value <0.285, THEN Final Solution = Retention' and 'IF ANN_I output value ${\geq}0.285$, THEN Final Solution = Churn.' The threshold 0.285 is the value optimized for the data used in this research. The result we present in this research is the structure or framework of our hybrid SVM model, not a specific threshold value such as 0.285. Therefore, the threshold value in the above discrimination rules can be changed to any value depending on the data. In order to evaluate the performance of our hybrid SVM model, we used the 'churn data set' in UCI Machine Learning Repository, that consists of 85% retention customers and 15% churn customers. Accuracy of the hybrid SVM model is 91.08% that is better than that of SVM_I model or SVM_B model. The points worth noticing here are its sensitivity, 95.02%, and specificity, 69.24%. The sensitivity of SVM_I model is 94.65%, and the specificity of SVM_B model is 67.00%. Therefore the hybrid SVM model developed in this research improves the specificity of SVM_B model while maintaining the sensitivity of SVM_I model.

• (The)Study of the Eastern Classic
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• no.62
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• pp.145-176
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• 2016

This paper aims to define the leadership of Gunja (君子, translated into prince, gentleman, or ideal man) based on Confucian Classics which offer the general values and norms of individuals' virtue and social virtuous acts. Thus, humanitarianism is regarded as true value, and the values of a virtuous person who properly practices social human relationships are discussed. The real worth of Gunja image is discussed as a true human image of "self-completion and completion of all things" (成己成物) which involves the convergence of truth, good and beauty where there is a sense of harmony and balance, where there is stern self discipline and self cultivation and where win-win values of human relationships are created. Confucian saint (聖人), wise man (賢人), great man (大人), and gentleman (君子) mean social leaders. They practice human morals, enlighten and beautify society with teachings, and are indicated as equipped with mental and material harmony, good character and competence, and economic power and morality. People today pursue their own personal growth according to their material preferences rather than pure intellectual cultural values, and are engrossed in visually beautiful external unlimited competition. In this digital age, we are supposed to demonstrate our individuality, but many people are obsessed with appearance, go on severe diet, and lose their health beauty, and consequently suffer mental stress. This trend fuels obsession with appearance and the sick practice of valuing appearance. As an alternative method to overcome this phenomenon, we need a leader image with the convergence of truth, good and beauty, which is characterized by internal self cultivation, external professionalism, and handsome and solid character. Confucian thoughts consist in practicing the Way of disciplining oneself for governing others (修己治人). Self discipline involves developing personal virtuous ability for cultivating a virtuous character, and governing others involves interacting to work together in society and to have right human relationships. Thus, leaders should impress not only themselves but also others. Self discipline for governing others means cultivating virtue for oneself and leading others. A true leader has self introspection and establishes himself through self discipline so that he can govern others or reach the realm of settling others where people live together. As all things have a value and a virtue, humans endeavor to cultivate character and virtue by learning and studying for securing their professionalism, reliability, character and ability, so as to create their own brand value. Personal character does not come from a high position, wealth and power. Character is a personal virtue, and is cultivated as immaculate and fresh through self discipline. As such, it well matches with a clean and clear spirit. This offers the ideal leader as the Guja image who has an extremely humane character, as well as being equipped with inherent virtues of intellect, benevolence and courage. Self development can foster virtue and self management through self leadership and self discipline. The leader in the relationship area can practice his virtue through virtuous acts, in other words, even think from another person's perspective. Such leader is mentioned as the principle of measuring square in the Great Learning. In our viewpoint, the beauty of character can breed the seed of virtue through intellect, benevolence and courage, the beauty of win-win can realize the right virtue by showing exemplary acts to others through considerateness, and the beauty of harmony can love and care for others like me through the principle of measuring square, thereby realizing the universal principle of virtue and harmony, which is like my mind. As such, the ideal leader, when his virtue and mind of being considerate of others all blending well, can exercise his ability to the full, can live together and coexist with many people, and can grow again into a triumphant relationship.

• Journal of the Ergonomics Society of Korea
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• v.35 no.4
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• pp.293-305
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• 2016

Objective: This study aims to measure cognitive load levels by analyzing the EEG of Koreans and foreigners, when they read a Korean text with care selected by level from the grammar and vocabulary aspects, and compare the cognitive load levels through quantitative values. The study results can be utilized as basic data for more scientific approach, when Korean texts or books are developed, and an evaluation method is built, when the foreigners encounter them for learning or an assignment. Background: Based on 2014, the number of the foreign students studying in Korea was 84,801, and they increase annually. Most of them are from Asian region, and they come to Korea to enter a university or a graduate school in Korea. Because those foreign students aim to learn within Universities in Korea, they receive Korean education from their preparation for study in Korea. To enter a university in Korea, they must acquire grade 4 or higher level in the Test of Proficiency in Korean (TOPIK), or they need to complete a certain educational program at each university's affiliated language institution. In such a program, the learners of the Korean language receive Korean education based on texts, except speaking domain, and the comprehension of texts can determine their academic achievements in studying after they enter their desired schools (Jeon, 2004). However, many foreigners, who finish a language course for the short-term, and need to start university study, cannot properly catch up with university classes requiring expertise with the vocabulary and grammar levels learned during the language course. Therefore, reading education, centered on a strategy to understand university textbooks regarded as top level reading texts to the foreigners, is necessary (Kim and Shin, 2015). This study carried out an experiment from a perspective that quantitative data on the readers of the main player of reading education and teaching materials need to be secured to back up the need for reading education for university study learners, and scientifically approach educational design. Namely, this study grasped the difficulty level of reading through the measurement of cognitive loads indicated in the reading activity of each text by dividing the difficulty of a teaching material (book) into eight levels, and the main player of reading into Koreans and foreigners. Method: To identify cognitive loads indicated upon reading Korean texts with care by Koreans and foreigners, this study recruited 16 participants (eight Koreans and eight foreigners). The foreigners were limited to the language course students studying the intermediate level Korean course at university-affiliated language institutions within Seoul Metropolitan Area. To identify cognitive load, as they read a text by level selected from the Korean books (difficulty: eight levels) published by King Sejong Institute (Sejonghakdang.org), the EEG sensor was attached to the frontal love (Fz) and occipital lobe (Oz). After the experiment, this study carried out a questionnaire survey to measure subjective evaluation, and identified the comprehension and difficulty on grammar and words. To find out the effects on schema that may affect text comprehension, this study controlled the Korean texts, and measured EEG and subjective satisfaction. Results: To identify brain's cognitive load, beta band was extracted. As a result, interactions (Fz: p =0.48; Oz: p =0.00) were revealed according to Koreans and foreigners, and difficulty of the text. The cognitive loads of Koreans, the readers whose mother tongue is Korean, were lower in reading Korean texts than those of the foreigners, and the foreigners' cognitive loads became higher gradually according to the difficulty of the texts. From the text four, which is intermediate level in difficulty, remarkable differences started to appear in comparison of the Koreans and foreigners in the beginner's level text. In the subjective evaluation, interactions were revealed according to the Koreans and foreigners and text difficulty (p =0.00), and satisfaction was lower, as the difficulty of the text became higher. Conclusion: When there was background knowledge in reading, namely schema was formed, the comprehension and satisfaction of the texts were higher, although higher levels of vocabulary and grammar were included in the texts than those of the readers. In the case of a text in which the difficulty of grammar was felt high in the subjective evaluation, foreigners' cognitive loads were also high, which shows the result of the loads' going up higher in proportion to the increase of difficulty. This means that the grammar factor functions as a stress factor to the foreigners' reading comprehension. Application: This study quantitatively evaluated the cognitive loads of Koreans and foreigners through EEG, based on readers and the text difficulty, when they read Korean texts. The results of this study can be used for making Korean teaching materials or Korean education content and topic selection for foreigners. If research scope is expanded to reading process using an eye-tracker, the reading education program and evaluation method for foreigners can be developed on the basis of quantitative values.

• Korean Security Journal
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• no.33
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• pp.197-228
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• 2012

The private security industry in Korea has rapidly proliferated. While the industry has grown quickly, though, private security officers have recently been implicated in incidents involving violence, demonstrating an urgent need for systematic reform and regulation of private security practices in Korea. Due to its quasi-public service character, the industry also risks losing the public's favor if it is not quickly disciplined and brought under legitimate government regulation: the industry needs professional standards for conduct and qualification for employment of security officers. This paper shares insights for the reform of the Korean private security industry through a study of the licensing and training requirements for private security businesses in the United States, mainly focusing on the Private Security Officer Employment Authorization Act (hereinafter the PSOEAA) and the California system. According to the PSOEAA, aspiring security officers shall submit to a criminal background check (a check of the applicants' criminal records). Applicants' criminal records should include not only felony convictions but also any other moral turpitude offenses (involving dishonesty, false statement, and information on pending cases). The PSOEAA also allows businesses to do background checks of their employees every twelve months, enabling the employers to make sure that their employees remain qualified for their security jobs during their employment. It also must be mentioned that the state of California, for effective management of its private security sector, has established a professional government authority, the Bureau of Security and Investigative Services, a tacit recognition that the private security industry needs to be thoroughly, professionally, and actively managed by a professional government authority. The American system provides a workable model for the Korean private security industry. First, this paper argues that the Korean private security industry should implement a more strict criminal background check system similar to that required by the PSOEAA. Second, it recommends that an independent professional government authority be established to oversee and enforce regulation of Korea's private security industry. Finally, this article suggests that education and training course be implemented to provide both diverse training as well as specialization and phasing.

• Journal of Intelligence and Information Systems
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• v.22 no.3
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• pp.71-89
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• 2016

Sentiment analysis is used for identifying emotions or sentiments embedded in the user generated data such as customer reviews from blogs, social network services, and so on. Various research fields such as computer science and business management can take advantage of this feature to analyze customer-generated opinions. In previous studies, the star rating of a review is regarded as the same as sentiment embedded in the text. However, it does not always correspond to the sentiment polarity. Due to this supposition, previous studies have some limitations in their accuracy. To solve this issue, the present study uses a supervised sentiment classification model to measure a more accurate sentiment polarity. This study aims to propose an advanced sentiment classifier and to discover the correlation between movie reviews and box-office success. The advanced sentiment classifier is based on two supervised machine learning techniques, the Support Vector Machines (SVM) and Feedforward Neural Network (FNN). The sentiment scores of the movie reviews are measured by the sentiment classifier and are analyzed by statistical correlations between movie reviews and box-office success. Movie reviews are collected along with a star-rate. The dataset used in this study consists of 1,258,538 reviews from 175 films gathered from Naver Movie website (movie.naver.com). The results show that the proposed sentiment classifier outperforms Naive Bayes (NB) classifier as its accuracy is about 6% higher than NB. Furthermore, the results indicate that there are positive correlations between the star-rate and the number of audiences, which can be regarded as the box-office success of a movie. The study also shows that there is the mild, positive correlation between the sentiment scores estimated by the classifier and the number of audiences. To verify the applicability of the sentiment scores, an independent sample t-test was conducted. For this, the movies were divided into two groups using the average of sentiment scores. The two groups are significantly different in terms of the star-rated scores.

• Asia pacific journal of information systems
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• v.24 no.2
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• pp.233-253
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• 2014

Can the stock market really be predicted? Stock market prediction has attracted much attention from many fields including business, economics, statistics, and mathematics. Early research on stock market prediction was based on random walk theory (RWT) and the efficient market hypothesis (EMH). According to the EMH, stock market are largely driven by new information rather than present and past prices. Since it is unpredictable, stock market will follow a random walk. Even though these theories, Schumaker [2010] asserted that people keep trying to predict the stock market by using artificial intelligence, statistical estimates, and mathematical models. Mathematical approaches include Percolation Methods, Log-Periodic Oscillations and Wavelet Transforms to model future prices. Examples of artificial intelligence approaches that deals with optimization and machine learning are Genetic Algorithms, Support Vector Machines (SVM) and Neural Networks. Statistical approaches typically predicts the future by using past stock market data. Recently, financial engineers have started to predict the stock prices movement pattern by using the SNS data. SNS is the place where peoples opinions and ideas are freely flow and affect others' beliefs on certain things. Through word-of-mouth in SNS, people share product usage experiences, subjective feelings, and commonly accompanying sentiment or mood with others. An increasing number of empirical analyses of sentiment and mood are based on textual collections of public user generated data on the web. The Opinion mining is one domain of the data mining fields extracting public opinions exposed in SNS by utilizing data mining. There have been many studies on the issues of opinion mining from Web sources such as product reviews, forum posts and blogs. In relation to this literatures, we are trying to understand the effects of SNS exposures of firms on stock prices in Korea. Similarly to Bollen et al. [2011], we empirically analyze the impact of SNS exposures on stock return rates. We use Social Metrics by Daum Soft, an SNS big data analysis company in Korea. Social Metrics provides trends and public opinions in Twitter and blogs by using natural language process and analysis tools. It collects the sentences circulated in the Twitter in real time, and breaks down these sentences into the word units and then extracts keywords. In this study, we classify firms' exposures in SNS into two groups: positive and negative. To test the correlation and causation relationship between SNS exposures and stock price returns, we first collect 252 firms' stock prices and KRX100 index in the Korea Stock Exchange (KRX) from May 25, 2012 to September 1, 2012. We also gather the public attitudes (positive, negative) about these firms from Social Metrics over the same period of time. We conduct regression analysis between stock prices and the number of SNS exposures. Having checked the correlation between the two variables, we perform Granger causality test to see the causation direction between the two variables. The research result is that the number of total SNS exposures is positively related with stock market returns. The number of positive mentions of has also positive relationship with stock market returns. Contrarily, the number of negative mentions has negative relationship with stock market returns, but this relationship is statistically not significant. This means that the impact of positive mentions is statistically bigger than the impact of negative mentions. We also investigate whether the impacts are moderated by industry type and firm's size. We find that the SNS exposures impacts are bigger for IT firms than for non-IT firms, and bigger for small sized firms than for large sized firms. The results of Granger causality test shows change of stock price return is caused by SNS exposures, while the causation of the other way round is not significant. Therefore the correlation relationship between SNS exposures and stock prices has uni-direction causality. The more a firm is exposed in SNS, the more is the stock price likely to increase, while stock price changes may not cause more SNS mentions.

• Journal of Nutrition and Health
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• v.48 no.1
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• pp.71-80
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• 2015

Purpose: The aim of this study was to investigate children's eating behaviors and teachers' feeding practices during mealtime at child-care centers. In addition, it focused on the difference of teachers' feeding practices on children age under 2 years ( ${\leq}2$ years old) and 3 years and older (3~5 years old). Methods: A total of 169 teachers working at childcare centers in Geumcheon-gu, Seoul, Korea, completed self-report questionnaires in December 2013. The questionnaires were composed of questions on children's eating behaviors, feeding practices; 'Explain', 'Praise', 'Modeling', 'Indulgent', 'Insist' and 'Reward', interaction with home, and a range of demographic information (analysis rate: 51.2%). Results: Approximately 59.2% of teachers had not taken a class on feeding practice and the average score for nutrition knowledge was 14.6 out of 30 points. The most undesirable eating behavior of children during mealtime was 'eating while walking around (36.7%)' both ' ${\leq}2$ years old' and '3~5 years old'. Regarding feeding practices according to children's undesirable eating behaviors during mealtime, there were differences between age groups. When children did not eat all of the foods that were served and did not clean up silverware or seats after having food, teachers caring for '3~5 years old' practiced 'Explain'. However, percentages of those who practiced 'Indulgent' and 'Modeling' were significantly higher in teachers caring for ' ${\leq}2$ years old' than '3~5 years old'. Conclusion: These findings indicated that teachers caring for children lack education and knowledge about nutrition and feeding practice. In addition, verbal feeding practices, like explain, were mainly used by teachers. As a result, for teachers, guidelines and programs for learning about age appropriate feeding practice during mealtime at child-care centers may be needed.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.1
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• pp.27-40
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• 2014

The functions of urban open space, which embraces community revitalization, are diverse. It is the means of public healthcare, learning centers for children, hub of arts and cultural programs, as well as promoter of urban tourism. However, in-depth discourse and research on the topic of urban open spaces has been limited so far. Hence, this study aims to investigate the motivations and satisfaction of visitation based on four representative waterfront open space in Seoul; Cheongyecheon Waterfront, Seoul Forest Park, Seonyudo Park and Banpo Hangang Park. The methods of study are literature review, observation investigation, and questionnaire survey. The findings are analyzed through the Exploratory Factor Analysis, Reliability Analysis, ANOVA Analysis and Regression Analysis by SPSS 18.0. The results of the study are as follows. First, urban waterfront open spaces in Seoul has 5 factors of visitor motivation; community amenity, nature access, cultural and educational assets, aesthetic enjoyment, and lastly means of escape. Second, factors of recognizing urban waterfront open spaces as community amenity and nature access indicate meaningful differences in visitor's perception by spatial characteristics. Third, distances between the destination and the visitor's residence influence significantly their perceived motivation. Close-range visitors perceived nature access as a principal factor, whilst medium to long-range visitors perceived visitation for aesthetic purposes more importantly. Lastly, the will to escape was shown as the influential factor in visitor satisfaction. Visiting open spaces for the enjoyment of nature and aesthetic purposes were factors that also closely relate to visitor satisfaction. In addition, it was found that there are different visitor motivations that influence visitor satisfaction in accordance with the spatial characteristics of each open space. In summary, it can be said that urban waterfront open space is a hybrid space connected to various types of urban contents beyond daily experiences. It was found that several visitor motivations including community development, design aesthetics, education and culture, entertainment, enjoyment of natural landscape, and relaxation, affect the overall satisfaction of the visiting experience. It is anticipated that the results of the study will be used by the local government in setting up strategies for the creation and management of successful urban waterfront open space, and for those involved in planning and design act as a starting point for spatial programming and amenities arrangement in accordance to the city's tourism and urban marketing approach.

• Korean Journal of Psychosomatic Medicine
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• v.13 no.2
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• pp.102-111
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• 2005

Objective : The purpose of this study was to investigate the quality of life and it's related factors in caregivers of attention deficit hyperactivity disorder patients. Methods : The subjects were 38 attention deficit hyperactivity disorder patients' caregivers(mean age : $37.5{\pm}6.5$, 38 women). Patients were diagnosed with DSM-IV-TR ADHD criteria. Korean version of WHOQOL-BREF(World Health Organization Quality of Life assessment instrument Abbreviated Version) was used for assessment. Results : 1) No significant differences were found in the score of WHOQOL-BREF, overall QOL, physical health domain, psychological domain, social relationships domain and environmental domain between caregiver and control group. 2) The score of Activity of daily living facet$(3.0{\pm}0.7\;vs.\;3.6{\pm}0.7)(p=0.008)$ and self-esteem facet $(2.8{\pm}0.7\;vs.\;3.3{\pm}0.7)(p=0.049)$ were significantly decreased in caregivers of ADHD. 3) Total score of WHOQOL-BREF(r=0.437, p=0.007) and physical health domain(r=0.370, p=0.024) were correlated with caregiver's educational age. 4) In the psychological domain, the score of self-esteem facet(r=-0.337, p=0.039) and thinking, learning, memory & concentration facet(r=-.341, p=0.036) were decreased with caregiver's age. 5) The score of environmental domain were significantly increased with caregiver's educational age (r=0.482, p=0.003), but decreased with patient's age(r=0.328, p=0.044). Conclusion : Although the quality of life in caregivers of ADHD patient had not significantly decreased than control, the quality of lift were positively correlated with educational age of caregives, and negatively correlated with chronological age of caregivers and children. Above results suggest that physicians should consider integrated approaches for caregiver's subjective quality of life in the management of ADHD.

• Journal of Distribution Science
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• v.10 no.1
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• pp.5-10
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• 2012

Currently, the rewards programs offered by many companies to strengthen customer relationships have been working quite well. In addition, many companies' rewards programs, designed for stabilizing revenue, are recognized to be effective. However, these rewards programs are not significantly differentiated between companies and there are no accurate conclusions currently, which can be made about their effects. Because of this, a company with a customer rewards program may not comprehend the true level of active participation. In this environment some companies' rewards programs inadvertently hinder business profitability as a side effect while attempting to increase customer loyalty. In fact, airline and oil companies pass on the financial cost of their programs to the customer, and as a result, they have been criticized publicly. The result of this is that the corporations with bad rewards programs tend to get a bad image. In this study of stores' rewards programs, we centered our focus on the design of the program. The main problem in this study is to recognize the financial value of the rewards program and whether it can create a competitive edge for the companies despite the cost issues experienced by them. Customers receiving financial rewards for their business may be just as satisfied with a particular company or store versus those who are not, and the program, perhaps, does not form a distinctive competitive advantage. When the customer is deciding between competing companies to secure their product needs with, we wanted to figure out how much of an affect a valuable reward program had on their decision making. To evaluate this, we set the first hypothesis as, "based on the level of involvement of the customers, there is a difference between customers' preferences for rewards programs." In the results of Experiment 1 we saw that in a financial compensation program for high-involvement groups and low-involvement groups, significant differences appeared and Hypothesis 1 was partially supported. As for the second hypothesis that "customers will have different preferences between a financial rewards programs (SE) and a joint rewards programs (JE)," the analysis showed that the preference for JE was significantly higher than that for other programs. In addition, through Experiment 2, we were able to find meaningful results, which revealed that consumers have shown a significant difference in their preferences between SE and JE. The purpose of these experiments was to enable the designing of a rewards program by learning how to enhance service information distribution and strengthen customer relationships. From the results, there should be a great amount of value for future service-related endeavors and academic research programs. The research is significant, because the results can be found to have a positive effect on reward program designs however, it does have the following limitations. First, this study was performed using an experiment, and all experiments have limitations. Second, although there was an individual evaluation and a joint evaluation, setting a proper evaluation criteria was difficult. In this study, 1,000 Korean won (KRW) in the individual evaluation had a value of 2 points, and, in the joint evaluation, 1,000 KRW had a value of 1 point. There may have been alternative ways to differentiate the evaluations to obtain the proper results. In this study, since there was no funding, the experiments were performed orally however, this was complementary to the study. Third, the subjects who participated in this experiment were students. Conducting this study through experimentation was unavoidable for us, and future research should be conducted using an actual program with the target customers.