現今因為網路的蓬勃發展，網路與人們的生活密不可分，在網站的
需求上，不管是購物網站或是音樂、影片網站，越來越多網站有個人化
的服務及推薦。若能有效的推薦商品給使用者，不但能增加使用者對此
網站的滿意度，還能讓這個網站的創造者獲得收益，造就雙贏的局面。
本篇論文利用兩種不同大小的電商資料，對使用者下一個可能會點
擊的商品做排序，推薦給使用者。為了將真正被點擊過的商品排在更前
面的推薦序列中，我們使用了四種不同類型的模型來做排序。由於最近
深度學習在各個領域表現卓越，推薦系統也開始使用深度學習架構來訓
練，但我們發現，在不同的電商規模下，使用深度學習架構不一定會表
現得比淺層的模型好。
在發現了這個現象之後，我們使用這四個不同的模型排序過後的序
列排名，來當作我們的訓練資料，並重新排序，最後我們得到了更符合使
用者歷史點擊的排名，將真正被點擊過的商品的排名往前排，並獲得明
顯的進步。不管在哪個資料集上，都表現的比四個基準模型還要好，並
在實驗過程中發現了商品排名與商品出現次數的相關性。

With the vigorous development of the Internet, it becomes inseparable
from people’s lives. Various websites, such as online retailers and online
music/video streaming websites, provide personalized recommendations to
show the RIGHT products to users. These recommendations may increase
users’ satisfaction with these services and create revenues for the service
providers.
This paper aims to predict a users’ next clicking item based on two
e-commerce datasets. We compared four ranking models and claimed a
model performs better if the model ranks the next clicking item at a former
position among the four models. Despite recent researches showed excellent
performance on deep learning-based ranking models, we found that this is
not always the case. Notably, we may need to consider the size of the
service providers as a reference to decide to apply a deep or a shallow
learning model.
Since different models may work under various scenarios, we developed
an ensemble model that learns to rank the items based on the rankings
returned by the four ranking models. Experimental results show that the
new model outperforms the four baselines: on both datasets, the new model
tends to put the next clicking item at a former position.

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