• Information Systems Review
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• v.23 no.4
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• pp.45-67
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• 2021

As the transaction volume of the C2C second-hand market is growing, the number of frauds, which intend to earn unfair gains by sending products different from specified ones or not sending them to buyers, is also increasing. This study explores the model that can identify frauds in the online C2C second-hand market by examining the postings for transactions. For this goal, this study collected 145,536 field data from actual C2C second-hand market. Then, the model is built with the characteristics from postings such as the topic and the linguistic characteristics of the product description, and the characteristics of products, postings, sellers, and transactions. The constructed model is then trained by the machine learning algorithm XGBoost. The final analysis results show that fraudulent postings have less information, which is also less specific, fewer nouns and images, a higher ratio of the number and white space, and a shorter length than genuine postings do. Also, while the genuine postings are focused on the product information for nouns, delivery information for verbs, and actions for adjectives, the fraudulent postings did not show those characteristics. This study shows that the various features can be extracted from postings written in C2C second-hand transactions and be used to construct an effective model for frauds. The proposed model can be also considered and applied for the other C2C platforms. Overall, the model proposed in this study can be expected to have positive effects on suppressing and preventing fraudulent behavior in online C2C markets.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.259-264
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• 2021

Recently, as the number of used trading sites supporting used trading increases, users want to search for a variety of information in real time. This new change has enabled a new type of C2C (Commerce to Commerce) transaction in the e-commerce base. However, since each used trading site has its own characteristics, it is difficult to standardize the whole. Therefore, in this paper, we studied a system that provides the transaction data used by the user in real time and provides the desired information quickly. In this paper, we researched the crawler system necessary for the development of the integrated trading system for used goods through Internet e-commerce, and made it possible to provide information in the web environment desired by the user through the defined morpheme analyzer. Therefore, in this study, we designed a system that provides information desired by users without accessing various used goods sites.

• Journal of Digital Convergence
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• v.19 no.7
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• pp.313-318
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• 2021

The purpose is to measure user experience in security-related services, focusing on Danggeun Market and Bungae Jangter, which are representative services in Korea among online trading of used goods. Using mobile applications, qualitative and quantitative research by conducting task experiments and surveys and in-depth interviews. As a result of the study, active interfaces are needed to make it easier for users to recognize safety and security services within current used trading platforms, a secure settlement method that benefits sellers, and services being provided to enhance security also need to consider graphical elements. This study is expected to help the continued development of safe used trading platforms considering security aspects on C2C-type platforms where buyers become sellers.

• Journal of the Korea Society of Computer and Information
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• v.27 no.3
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• pp.173-182
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• 2022

In this paper, we propose a machine learning model that can prevent fraudulent transactions in advance and interpret them using the XAI approach. For the experiment, we collected a real data set of 12,258 mobile phone sales posts from Joonggonara, a major domestic online C2C resale trading platform. Characteristics of the text corresponding to the post body were extracted using Doc2vec, dimensionality was reduced through PCA, and various derived variables were created based on previous research. To mitigate the data imbalance problem in the preprocessing stage, a complex sampling method that combines oversampling and undersampling was applied. Then, various machine learning models were built to detect fraudulent postings. As a result of the analysis, LightGBM showed the best performance compared to other machine learning models. And as a result of SHAP, if the price is unreasonably low compared to the market price and if there is no indication of the transaction area, there was a high probability that it was a fraudulent post. Also, high price, no safe transaction, the more the courier transaction, and the higher the ratio of 0 in the price also led to fraud.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.61-68
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• 2023

As global growth has gradually declined, the Customer to Customer (C2C) market has expanded. And the growth potential of the C2C market is getting higher than in the past. Therefore, in this study, we examined what factors affect the price of used products within the C2C market. In order to examine the factors, we used data provided by Kaggle, which is a data science platform, and Mercari, Japan's largest C2C community marketplace platform. In research methods, the characteristics of the products were selected such as product categories, product status, shipping costs, product brands, and the data were analyzed using a linear mixing model to predict the price of C2C used goods. As a result, the variable that most affected the price was the shipping cost. When the seller paid for the shipping cost, the price would drop more than if the buyer had to pay. This study has been shown that the shipping costs is also an important factor in the used market, which can provide practical implications for customers of real transactions.

• Fashion & Textile Research Journal
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• v.23 no.3
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• pp.358-369
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• 2021

This study aims to classify the dimensions of the sales information of secondhand clothing goods on the C2C secondhand trading platform and to systematically analyze the components of each dimension. To this end, the NVivo 12.0 qualitative data analysis software was used. The content analysis showed that the sales information of secondhand clothing goods was classified into four dimensions: detailed information of the sale goods, information specific to secondhand clothing goods, seller opinion information, and service information. The components of each dimension were as follows. The detailed information of the sale goods included size, sale price, item, design, brand name, material, color, wearing season, fit, gender, etc. The information specific to secondhand clothing goods included the number of times the item was worn, its purchase history, and product condition. Seller opinion information included product review, sales motivation, notes for the transaction, coordination proposal, and usage proposal. The service information included the transaction mode, exchange·return·refund, and promotion. The frequency analysis showed that the highest frequencies were sale goods(37.47%), information specific to secondhand clothing goods(24.63%), seller opinion information(20.54%), and service information(17.37%). This study will help C2C secondhand trading platform managers or sellers establish clear standards for presenting sales information and developing ideas toward constructing differentiated platform contents.

• Journal of Industrial Convergence
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• v.20 no.12
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• pp.179-186
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• 2022

This study aims to develop a predictive model to suggest a used sales price to sellers and buyers when trading used tablet PCs. For model development, we analyzed the real used tablet PC transaction data and additionally collected detailed product information. We developed several predictive models and selected the best predictive model among them. Specifically, we considered a multiple linear regression model using the used sales price as a dependent variable and other variables in the integrated data as independent variables, a multiple linear regression model including interactions, and the models from stepwise variable selection in each model. The model with the best predictive performance was finally selected through cross-validation. Through this study, we can predict the sales price of used tablet PCs and suggest appropriate used sales prices to sellers and buyers.

• Journal of the Korean Home Economics Association
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• v.44 no.4 s.218
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• pp.175-190
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• 2006

The purpose of this research is to investigate consumers' experience of using Internet used-item markets in order to determine their motives in such activity. In terms of the Internet used-item market, (1) it contributes to a sound culture of consumption by recycling, (2) as a C2C market, it retains characteristics fundamentally different from the existing one-way type of market, (3) and it offers different characteristics from existing offline-based flea markets. Two significant themes emerged from the study results. First, users of Internet used-item markets passed through various stages such as novice, addict, and expert and learned the techniques for utilizing the used-item market. Second, for fast transactions with generalized Internet banking and the increasing trend for price bargaining emotional exchange among members is being transformed into the pursuit of transactional efficiency.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.609-615
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• 2022

In this paper, we propose a monitoring system for illegal overseas direct purchase based on C2C transaction between individuals. The Customs Act stipulates that direct purchases from overseas are exempted from taxation only if they are less than a certain amount (US$150, but US$200 in the US) or are recognized as self-used goods. The act of reselling overseas direct purchase items purchased with exemption from taxation online, etc., is a crime of smuggling without a report. Nevertheless, the number of re-sells on online second-hand websites is increasing, and it is becoming a controversial social issue of continuous violation of the Customs Act. Therefore, this study collects unspecified transaction details related to overseas direct purchase, refines the data in a big data method, and designs it as a monitoring system through natural language processing, etc. analyzed. It will be possible to use it to crack down on illegal transactions of overseas direct purchase goods.

• Journal of Information Technology Services
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• v.14 no.1
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• pp.69-83
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• 2015

The e-commerce market has been more diversified via B2B or P2P, and the size of this market has gradually been expanded as well. A noteworthy phenomenon is the P2P market, which has shown a rapid, approximately 200-fold or more increase in size since 2005. Specifically, the online secondhand-goods market that makes transaction easier and more convenient has attained a fast growth as well, but either sellers or buyers of secondhand goods are properly protected due to a lack of legal regulations on secondhand-goods transaction. The purpose of this study was to examine problems with online secondhand-goods transaction and to suggest some reform measures. There is something wrong with the legal status of brokers for secondhand-goods sales. According to the current law, individual brokers are neither mail-order sellers nor mail-order brokers. So they don't have lots of liabilities, and it means that the burden of risk is all imposed on buyers. Therefore it's suggested that individual brokers should be defined as 'involved operator of electronic commerce' so that proper liability might be imposed on them.