Journal of Intelligence and Information Systems (지능정보연구)

Korea Intelligent Information System Society (한국지능정보시스템학회)
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Application of diversity of recommender system accordingtouserpreferencechange

사용자 선호도 변화에 따른 추천시스템의 다양성 적용

  • Na, Hyeyeon (Graduate School of Interdisciplinary Management, Ulsan National Institute Science and Technology (UNIST)) ;
  • Nam, Kihwan (Management Information Systems, Business School, Dongguk University)
  • 나혜연 (울산과학기술원 융합경영대학원) ;
  • 남기환 (동국대학교 경영대학 경영정보학과)
  • Received : 2020.11.13
  • Accepted : 2020.12.16
  • Published : 2020.12.31
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Abstract

Recommender Systems have been huge influence users and business more and more. Recently the importance of E-commerce has been reached rapid growth greatly in world-wide COVID-19 pandemic. Recommender system is the center of E-commerce lively. Top ranked E-commerce managers mentioned that recommender systems have a major influence on customer's purchase such as about 50% of Netflix, Amazon sales from their recommender systems. Most algorithms have been focused on improving accuracy of recommender system regardless of novelty, diversity, serendipity etc. Recommender systems with only high accuracy cannot satisfy business long-term profit because of generating sales polarization. In addition, customers do not experience enjoyment of shopping from only focusing accuracy recommender system because customer's preference is changed constantly. Therefore, recommender systems with various values need to be developed for user's high satisfaction. Reranking is the most useful methodology to realize diversity of recommender system. In this paper, diversity of recommender system is represented through constructing high similarity with users who have different preference using each user's purchased item's category algorithm. It is distinguished from past research approach which is changing the algorithm of recommender system without user's diversity preference level. We tried to discover user's diversity preference level and observed the results how the effect was different according to user's diversity preference level. In addition, graph-based recommender system was used to show diversity through user's network, not collaborative filtering. In this paper, Amazon Grocery and Gourmet Food data was used because the low-involvement product, such as habitual product, foods, low-priced goods etc., had high probability to show customer's diversity. First, a bipartite graph with users and items simultaneously is constructed to make graph-based recommender system. However, each users and items unipartite graph also need to be established to show diversity of recommender system. The weight of each unipartite graph has played crucial role changing Jaccard Distance of item's category. We can observe two important results from the user's unipartite network. First, the user's diversity preference level is observed from the network and second, dissimilar users can be discovered in the user's network. Through the research process, diversity of recommender system is presented highly with small accuracy loss and optimalization for higher accuracy is possible controlling diversity ratio. This paper has three important theoretical points. First, this research expands recommender system research for user's satisfaction with various values. Second, the graph-based recommender system is developed newly. Third, the evaluation indicator of diversity is made for diversity. In addition, recommender systems are useful for corporate profit practically and this paper has contribution on business closely. Above all, business long-term profit can be improved using recommender system with diversity and the recommender system can provide right service according to user's diversity level. Lastly, the corporate selling low-involvement products have great effect based on the results.

추천시스템은 시간이 흐를수록 사용자와 기업에게 점점 더 큰 영향을 주고 있다. 최근 코로나(COVID-19) 팬데믹 현상이 전 세계적으로 일어나면서 세대를 뛰어넘어 E-Commerce의 중요성이 증대되었고 추천시스템은 E-Commerce 활성화의 최중심에 있다. 추천시스템이 개발된 이래로 다수의 알고리즘이 추천시스템의 정확도를 올리는 것에 집중되어 있었고, 추천시스템의 희귀성, 다양성, 우연성 등과 같은 다른 가치들이 간과되고 있다. 본 논문에서는 사용자의 만족도는 추천시스템의 정확도에만 달려있지 않고 다양한 성능을 겸비했을 때 고객에게 만족스러운 추천서비스 경험을 제공할 것이라 생각하여 다양성을 위한 그래프 기반의 추천시스템을 개발하였다. 사용자 네트워크를 구성한 뒤 카테고리를 활용한 무게중심변화를 통해 유사도가 낮은 이질적인 사용자를 찾아 추천상품의 유사성을 낮추는 방식으로 다양성을 도모하였다. 또한, 추천의 다양성은 사용자의 다양성 선호 수준에 따라 상이할 것이라는 가정에 따라 사용자의 다양성 선호 수준을 구별하였고 다양성 모델 성능이 사용자 특성별로 다름을 확인할 수 있었다. 전체 연구 결과, 추천시스템의 정확성과 다양성이 트레이드 오프 관계에 놓여있다는 것을 확인할 수 있었지만 본 연구모델을 통해 근소한 정확도 손실 대비 높은 다양성을 얻을 수 있었다. 본 연구는 그래프 기반의 추천시스템을 통해 사용자의 만족도를 향상시키는 다양성을 실현하였다는 연구적 의의와 사용자 수준을 고려한 추천의 다양성을 적용 결과를 통해 기업의 장기적 이윤을 상승시킬 수 있는 모델 개발이라는 실무적 의의를 꼽을 수 있다.

Keywords

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