• Information Systems Review
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• v.9 no.2
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• pp.109-127
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• 2007

In a buyer seller transaction process, "value for money" is one of the most important criteria for a buyer's purchasing decision. The terms "value" and "money" represent a composite measure of what a buyer receives from goods and/or services and a measure of what he/she pays for them, respectively. The purpose of this paper is to help buyers select the best seller in terms of value for money. We suggest DEA models for buyer seller transactions and apply them to the case of an Internet comparison shopping site in Korea. We expect our DEA models to provide valuable information for rational buyers who want to pay the least price for high quality products/services. Moreover, we expect that our models can help sellers be more competitive by showing them how to attract buyers.

• Journal of Cadastre & Land InformatiX
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• v.47 no.1
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• pp.143-160
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• 2017

Since officially assessed land price system was introduced, it has functioned as the criterion for establishing and implementing real estate policies. However, there is a controversial issue about the adequacy of the officially assessed land price system. The problem is that it is difficult to establish a statistical model due to too many land characteristics. Also, local economy, macroeconomic environments and development plans are not reflected in the land price evaluation model. Considering longitudinal and cross-sectional variables, a two-way error component panel model was used in this study. This analysis model includes variables reflecting land characteristics, macroeconomic volatility, and development project. The Paju LCD Industrial Complex was selected as a analysis area and an empirical analysis was performed. According to the analysis, the number of significant land characteristic variables were 14(31%) under 5% significance level. Macroeconomic volatility has had an influence on the land price and year variable reflecting development project has consistently been significant since the industrial complex was designated. Therefore, this study suggests that the land price evaluation model should be improved by simplifying land characteristic variables and including macroeconomic and regional economic variables.

• The Korean Journal of Financial Management
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• v.26 no.1
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• pp.65-94
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• 2009

The event of change in KOSPI 200 Index composition is one of the main subjects for the test of EMH. According to EMH, when a certain event is not related with firm's fundamental value, stock price should not change after the announcement of news. This hypothesis leads us to the conclusion of horizontal demand curve of stock. This logic was questioned by Shleifer(1986) and argued that downward sloping demand curve hypothesis was supported. But Harris and Gruel(1986) found a different empirical evidence that price reversal occurs in the long run, which is called price pressure hypothesis. They argued that short term price effect by large block trading (price pressure) is offset in the long run because these event is unrelated to fundamental value. Therefor, they argued that EMH can not be rejected in the long run. Until now, there are two empirical studies with Korean market data in this area. Using a data with same time period of $1996{\sim}1999$, Kweon and Park(2000) and Ahn and Park(2005) showed that stock price or beta is not significantly affected by change in index composition. This study retested this event expanding sample period from 1996 to 2006, and analyzed why this event was considered an uninformative events in the preceding studies. We analyzed a market impact by separating samples according to firm size and market condition. In case of newly enlisted firm, we found the evidence supporting price pressure hypothesis on average. However, we found the long run price effect in the sample of large firms under bearish markets. At the same time, we know that the number of samples under the category of large firms under bearish markets is relatively small, which drives the same result of supporting the hypothesis that change in index composition is a non-informative event on average. Also, the long run price effect of large size firms under bearish markets was supported by the analyses using trading volumes. On the other hand, in case of delisting from the index, we found the long run price effect but that was not supported by trading volume analyses.

• The Journal of Society for e-Business Studies
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• v.16 no.3
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• pp.191-209
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• 2011

In a buyer-seller transaction process, 'value for money,' a measure of quality-price-ratio, is one of the most important criteria for buyers' purchasing decisions. The purpose of this paper is to suggest a method which helps online shoppers choose the best of several sellers offering homogeneous goods. We suggest FDH (free disposal hull) model, an applied model of data envelopment analysis (DEA), for online buyer-seller transactions and verify it with the data from an Internet comparison shopping site. For this purpose, we analyze consumer choice behaviors by examining how consumers respond to different sale conditions such as price, brand, or delivery time. Then, we implement a seller recommendation system to support buyers' purchasing decisions. We expect our FDH model to provide valuable information for rational buyers who want to pay the least price for high quality products/services and to be used in implementing automated evaluation processes in micro transactions. Moreover, we expect that our results can be utilized for sellers' benchmarking strategies which help sellers be more competitive by showing them how to attract buyers.

• Korean Journal of Agricultural Science
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• v.33 no.1
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• pp.43-56
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• 2006

In this thesis we aim at analyzing international competitive power of Chinese ginseng in comparison with Korean ginseng and searching policy direction for Korea to compete Chinese ginseng industry. We summarized the research results as follows; First, we examine the structural change of ginseng industry of China. Second, we review the theories for international competitiveness and apply the method of analyzing competitiveness to ginseng industry. Third, we compared the international competitive power of the ginseng industry between China and Korea and found that Chinese ginseng, estimated by Revealed Comparative Advantage(RCA) at about 15, still remains high competitiveness in terms of cost and price but lowering price competitiveness recently. Based on the research results, we suggest export promotion strategies of the Korean ginseng as follows; 1) Korean government should enforce trade cooperation with China so as to register Korean root ginseng an importable medicine. 2) Korean ginseng producer should develop various products such as capsules, powders and etc. according to China's consumer purchasing power and taste. 3) Korean ginseng should be sold as an differentiated commodity so that it will contribute to building consumer loyalty to Korean ginseng, makes market share superior to other cheaper ginseng products in China. 4) In order to be effective brand marketing and product advertisement, there should be established reliable networks to process and distribute Korean ginseng products exclusively.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.1
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• pp.39-48
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• 2011

Uses a Tomographic scan image and Table Object Distance(TOD) price after measuring, uses accuracy and usability of blood vessel diameter(Vessel Diameter) measurement under comparison evaluating boil TOD Calibration. The patient who enforces Prosecuting Attorney abdomen Tomographic scan in the object the superior mesentery artery uses PACS View from abdomen fault image and from blood vessel diameter and the table measures the height until of the blood vessel. Uses Angio Catheter from Angiography(5 Fr.) and enforces is measured from PACS View the height until of the table which and the blood vessel at TOD Calibration price and the size of the superior mesentery artery inputs measures an superior mesentery artery building skill. Catheter Calibration input Agnio Catheter where uses in Angiography the size of the superior mesentery artery at Catheter Calibration price and they measure. Produced an accuracy from monitoring data and comparison evaluated. The statistical program used SPSS. TOD Calibration accuracy was 96.53%, standard deviation is 0.03829. Catheter Calibration accuracy of 92.91%, standard deviation is 0.05085. Represents a statistically significant difference(p = 0). According to age and gender was not statistically significant(p > 0.05). TOD Calibration correlation coefficient R-squared of 88.8%, Catheter Calibration of the R-squared is 75.5%. High accuracy of both methods. Through this study, CT images using the measured distance between the table and the Object, TOD Calibration accuracy higher than two Catheter Calibration was measured. TOD and Catheter Calibration represents a statistically significant difference(p = 0).

• The Journal of the Korea Contents Association
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• v.18 no.9
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• pp.623-632
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• 2018

Both investors and researchers are attentive to the prediction of stock price movement directions since the accurate prediction plays an important role in strategic decision making on stock trading. According to previous studies, taken together, one can see that different factors are considered depending on stock markets and prediction periods. This paper aims to analyze what data mining techniques show better performance with some representative index and stock price datasets in the Korea stock market. In particular, extreme gradient boosting technique, proving itself to be the fore-runner through recent open competitions, is applied to the prediction problem. Its performance has been analyzed in comparison with other data mining techniques reported good in the prediction of stock price movement directions such as random forests, support vector machines, and artificial neural networks. Through experiments with the index/price datasets of 12 years, it is identified that the gradient boosting technique is the best in predicting the movement directions after 1 to 4 days with a few partial equivalence to the other techniques.

• Journal of the Korean Operations Research and Management Science Society
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• v.42 no.2
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• pp.1-17
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• 2017

Based on increased popularity and use of social network services as a marketing tool, social commerce became an emerging trend in e-commerce platforms. Social commerce involves sellers offering potential consumers the products and services at a lower price in a limited time period. Through comparison of the performances of domestic social commerce websites, we found that the buying environment such as price, number of available products, and the remaining time period for sale has a significant difference influencing on the purchase decisions of consumers. This study aims to analyze the interaction effects and preference levels of four characteristics (price, discount rate, number of purchases and purchase time) by conducting choice-based conjoint analysis. Survey experiment was performed using a sample of 146 undergraduate and graduate students. The results showed that consumers importantly consider purchase time, discount rate, price, number of purchases in the order of their preference. Also, discount effect is more significant on purchase decisions than price effect and consumers distinguish less the differences among the buying environment characteristics in the closing days of purchase period. Customer segmentation using the preference levels of characteristics indicates that the preference levels have different effects in the purchase utility of each segment. The proposed customer segmentation and differences in feature utilities are expected to be valuable in forming future sales promotion strategies in social commerce.

• Environmental and Resource Economics Review
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• v.25 no.4
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• pp.495-516
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• 2016

This study empirically examines how asymmetric price adjustment of the retail gas price happens differently for various oil products, such as high-grade gasoline, regular gasoline, and diesel, by employing asymmetric error correction model within weekly data set from 2010~2015. Our estimation results show that the price adjustment, across the all oil types, predicated on shifting crude oil and wholesale oil prices is asymmetric. In addition, the duration of asymmetry was shorter in high-grade gasoline case than in other oil types. This took place by rapid price adjustment of high-grade gasoline price when faced with both cost increases and decreases, in comparison with regular gasoline and diesel cases. There results were attributed by characteristics of the consumer group and a high retail-wholesale margin of high-grade gasoline.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.181-192
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• 2016

We consider several methods to approximate option prices with correction terms to the Black-Scholes option price. These methods are able to compute option prices from various risk-neutral distributions using relatively small data and simple computation. In this paper, we compare the performance of Edgeworth expansion, A-type and C-type Gram-Charlier expansions, a method of using Normal inverse gaussian distribution, and an asymptotic method of using nonlinear regression through simulation experiments and real KOSPI200 option data. We assume the variance gamma model in the simulation experiment, which has a closed-form solution for the option price among the pure jump $L{\acute{e}}vy$ processes. As a result, we found that methods to approximate an option price directly from the approximate price formula are better than methods to approximate option prices through the approximate risk-neutral density function. The method to approximate option prices by nonlinear regression showed relatively better performance among those compared.