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Reducing Noise Using Degree of Scattering in Collaborative Filtering System

협력적 여과 시스템에서 산포도를 이용한 잡음 감소

  • 고수정 (인덕대학 컴퓨터소프트웨어과)
  • Published : 2007.12.31

Abstract

Collaborative filtering systems have problems when users rate items and the rated results depend on their feelings, as there is a possibility that the results include noise. The method proposed in this paper optimizes the matrix by excluding irrelevant ratings as information for recommendations from a user-item matrix using dispersion. It reduces the noise that results from predicting preferences based on original user ratings by inflecting the information for items and users on the matrix. The method excludes the ratings values of the utmost limits using a percentile to supply the defects of coefficient of variance and composes a weighted user-item matrix by combining the user coefficient of variance with the median of ratings for items. Finally, the preferences of the active user are predicted based on the weighted matrix. A large database of user ratings for movies from the MovieLens recommender system is used, and the performance is evaluated. The proposed method is shown to outperform earlier methods significantly.

협력적 여과 시스템의 사용자-아이템 행렬은 사용자들이 아이템에 대하여 평가할 경우 사용자들의 감정 상태가 일정하지 않음으로 인하여 평가 결과에 잡음을 포함할 가능성이 높다. 이러한 문제점을 해결하기 위해 본 논문에서는 산포도를 이용하여 추천 정보로서 이용하기에 부적당한 평가값들을 제외시킴으로써 사용자-아이템 행렬을 최적화시키고, 아이템 정보와 사용자 정보를 반영하여 고유의 사용자의 평가값을 기반으로 선호도를 예측하였을 때 발생하는 잡음을 감소시킨다. 산포도의 변이계수가 갖는 단점을 보완하기 위하여 백분위수를 이용하여 극한적인 평가값을 제거하고, 사용자의 변이계수와 아이템의 중위수를 병합하여 가중치가 부여된 사용자-아이템 행렬을 구성한다. 마지막으로 이를 기반으로 새로운 사용자의 선호도를 예측한다. 제안된 방법은 영화에 대해 평가한 MovieLens 시스템의 데이터베이스를 이용하여 평가되었으며, 기존의 방법보다 성능이 높음을 보인다.

Keywords

References

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