From 58f20db847e39dd3414018817f780b3373a66437 Mon Sep 17 00:00:00 2001 From: "hannes.kuchelmeister" Date: Wed, 15 Apr 2020 17:53:05 +0200 Subject: [PATCH] add explanation about aggregation strategies --- 30_Thesis/sections/10_foundations.tex | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/30_Thesis/sections/10_foundations.tex b/30_Thesis/sections/10_foundations.tex index 5ebe1a0..709c36b 100644 --- a/30_Thesis/sections/10_foundations.tex +++ b/30_Thesis/sections/10_foundations.tex @@ -194,6 +194,20 @@ A group recommender system is a recommender system aimed at making recommendatio \todo[inline]{example of a group recommender} \todo[inline]{go more into detail about preference aggregation} +Merging preferences has to be done using an aggregation strategy. This section presents three strategies: multiplication, average and least misery. The multiplication strategy multiplies preferences of users and thereby combines them into a group preference. Similarly the average strategy takes the average of a rating and the least misery strategy takes the lowest rating among group members. To illustrate the example in \autoref{tab:Foundations:RecommenderSystem:MoviePreferences} is used. A group is formed out of Lucy, Eric and Diane. The resulting ratings for each strategy are shown in \autoref{tab:Foundations:RecommenderSystem:AggregationStrategy}. + +\begin{table} + \centering + \begin{tabular}{ l | c | c | c | c | c } + & The Matrix & Titanic & Die Hard & Forest Gump & Wall-E \\ \hline + multiplication & 8 & - & 30 & 75 & - \\ + average & $\frac{7}{3}$ & - & $\frac{10}{3}$ & $\frac{13}{3}$ & - \\ + least misery & 1 & - & 2 & 3 & - \\ + \end{tabular} + \caption{An example showing preference aggregation strategies for a group using the data from \autoref{tab:Foundations:RecommenderSystem:MoviePreferences}. Titanic and Wall-E were left out because not all group members have rated these movies.} + + \label{tab:Foundations:RecommenderSystem:AggregationStrategy} +\end{table} \section{Base Recommender System}