본 연구는 기존의 협업필터링 기반 상품추천시스템의 추천품질과 신뢰도를 높이기 위하여 설명기능을 추가한 WebCF-Exp추천시스템을 개발하고 그 시스템의 성능을 평가하고자 한다. 기존의 협업필터링 기반 상품추천시스템은 추천 성능의 우수함에도 불구하고 사용자들에게 추천의 이유를 설명하는 기능이 없으므로, 고객이 추천한 상품에 대한 신뢰감이 부족해지기 쉬운 단점이 있다. 이 연구는 기존의 웹마이닝과 상품계층도를 적용한 협업필터링 기반 상품추천 시스템에 추천한 이유를 고객에게 제공함으로써 고객이 그 시스템을 신뢰할 수 있도록 도움을 주기 위한 여러 형태의 설명기능을 제공한다. 또한 이러한 설명기능을 추가한 추천시스템 WebCF-Exp을 개발하고, 그 효용성을 검증하기 위한 실험을 위하여 인터넷 쇼핑몰을 구현하였다. 마지막으로, 가상의 인터넷 쇼핑몰을 이용한 고객들을 대상으로 온라인 설문을 통해 각기 다른 20개의 설명인터페이스 중 과연 어떤 인터페이스가 고객들이 이해하기에 가장 적합한지와 추천된 상품에 설명기능이 추가 되었을 때 사용자들의 구매 의사결정에 어느 정도 도움을 줄 수 있는지를 분석하였다.
The continuous growth of the Internet and e-commerce has allowed companies to provide customers with more choices on products. Increasing choice has also caused product overload where the customer is no longer able to effectively choose the products he/she is exposed to. A promising technology to overcome the product overload problem is recommender systems that help customers find the products they would like to purchase. To date, a variety of recommendation techniques have been developed. Collaborative Filtering (CF) is the most successful recommendation technique, which has been used in a number of different applications such as recommending movies, articles, books, Web pages, etc. However, its widespread use has exposed some limitations, such as sparsity, scalability, and black box. Many researchers have focused on sparsity and scalability problems but a little has tried to solve the black box problem. Most CF recommender systems are black boxes, providing no transparency into the working of the recommendation. To overcome the black box problem, it is developed a recommender system named WebCF-Exp (Web usage mining driven Collaborative Filtering with Explanation facilities). Explanation facilities make it possible to expose the reasoning and data behind a recommendation. Therefore, they provide us with a mechanism for handling errors that come with a recommendation. Furthermore, it is proposed to use web usage mining and product taxonomy to enhance the recommendation quality for e-commerce environment. Web usage mining populates the rating database by tracking customers’shopping behaviors in the Web, thereby leading to better recommendations. The product taxonomy is used to improve the performance through dimensionality reduction of the rating database.The overall procedure of WebCF-Exp consists of two phases: recommendation phase and explanation phase. The recommendation phase is divided into four sub-phases: grain specification, customer profile creation, neighborhood formation, and recommendation generation. The explanation phase consists of white box model and black box model. A white box model is one way to build explanation interfaces using detailed process or data such as neighbor ratings, the ratio of click, and the ratio of purchase. Black box model is the other way of which there is no detailed process or data available. In black box model, we focus on ways to justify recommendation that are independent of the process such as marketing or event information.WebCF-Exp recommender system is operated by four agents: Web log analysis agent, Data transformation agent, Recommendation agent, and Explanation agent. Web log analysis agent manages Web log database through periodic collecting, parsing and analyzing Web server log files such as access logs, referrer logs, agent logs and cookie files. Thus, the users can easily access and analyze them like other operation databases. Data transformation agent creates and manages the data mart that provides data indispensable to accomplish recommendation tasks. Recommendation agent makes a personalized recommendation list for each target customer. Explanation agent provides interfaces which expose the reasoning and data behind a recommendation. Twenty different explanation interfaces are developed as white box model and black box model. To test the performance of WebCF-Exp, it is developed a prototype internet shopping mall named EBIB (e-Business & Intelligent Business) and interactive interfaces. Experiments are conducted with the data provided by EBIB Research Internet shopping mall. Our experimental result shows that WebCF-Exp recommendation system shows better performance than the CF recommendation system without explanation facilities. And explanation types of five stars, simple graph, and showing the evaluation results of similar customers, show better performance than other types. Furthermore, as customers understand explanation interfaces better, it results that customers purchase more products.