Revisiting the Multi-Criteria Recommender System of a Learning Portal
AVG Coverage
4.2 Synthetic Data Set
;=+&+T+<*7"$)&$P&7=+&<()I"I(7+&(,1$0"7=?%&$M+0&7=+&%3)7=+7"<&ai%"?&I(7(%+7&%++?+I&7$& G+0P$0?&?*<=&R+77+0&$M+0&7=+&$0"1")(,&ai0+(,&$)+.&(%&$)+&:$*,I&=(M+&+TG+<7+I&W%")<+& (&?$0+&I+)%+&M+0%"$)&$P&7=+&I(7(%+7&=(%&R++)&<0+(7+IX@&8%&"7&"%&(,%$&%=$:)&")&;(R,+&5.& 7=+&?(Q$0"73&$P&7=+&$*7%7()I")1&M(0"(7"$)%&=(M+&(&0(7=+0&1$$I&<$M+0(1+&7=(7&"%&<,$%+&7$& WP$0&FU;X&()I&?$0+&7=()&WP$0&'!!X&NLk@&&
6*0G0"%")1,3& 7=+& '8i& 0+%*,7%& %++?& 7$& R+& (7& 7=+& ,+M+,& $P& 7=+& non-personalised& (,1$0"7=?%&W(,%$&G0+%+)7+I&")&;(R,+&-X&()I&(0$*)I&L@lN&P$0&7=+&PG MNN Euclidian
Simple Mean& ()I& 7=+& PG CWT Cosine Simple Mean@& H7& %++?%& 7=(7& M+03& %"?G,+&
(,1$0"7=?%&7=(7&<0+(7+&:+"1=7+I&%*?%&$P&7=+&G(%7&0(7")1%.&%*<=&(%&7=+&Arithmetic Mean& ()I& 7=+& Geometrical Mean.& ?(3& G0$M"I+& G0+I"<7"$)%& 7=(7& =(M+& ,+%%& '8i& 7=()& 7=+& <$,,(R$0(7"M+&P",7+0")1&M(0"(7"$)%@&;="%&<$*,I&R+&I*+&7$&7=+&P(<7&7=(7&7=+&%"?*,(7+I&*%+0%& =(M+&G0$M"I+I&(II"7"$)(,&0(7")1%&:"7=&%"?",(0&I"%70"R*7"$)%&R*7&%7",,&%*<=&(&%"?G,"%7"<& ")7+0G0+7(7"$)&$P&7="%&$R%+0M(7"$)&"%&)$7&+)$*1=@&81(").&7=+&10(G="<(,&",,*%70(7"$)%&$P&
Y"1*0+%& B& ()I& [& %=$:& 7=(7& ")& ?$%7& <(%+%& 7=+& PG& M(0"(7"$)%& %++?& 7$& R+& G+0P$0?")1& R+77+0& 7=()& 7=+& AS ()I& WS& $)+%.& (,7=$*1=& 7=+& I"PP+0+)<+%& (0+& %?(,,@& ;$& P*07=+0& ")M+%7"1(7+& :="<=& :$*,I& R+& 7=+& ?$0+& (GG0$G0"(7+& (,1$0"7=?& M(0"(7"$)%& 7$& %*GG$07& 0+<$??+)I(7"$)& ")& a01()"<@iI*)+7& ")& %*<=& (& P*7*0+& %<+)(0"$.& :+& I"I& ()& (II"7"$)(,& +TG+0"?+)7(,&()(,3%"%@&&
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Fig. 4.& '8i& ?+70"<& G+0P$0?()<+& P$0& 7$G9A& '!!& M(0"(7"$)%& P0$?& (,,& <()I"I(7+& M(0"(7"$)%&$M+0&ai%"?&I(7(&%+7&
&
'$0+& %G+<"P"<(,,3.& :+& ")M+%7"1(7+I& 7=+& G+0P$0?()<+& $P& 7=+& 7:$& (,1$0"7=?%& 7=(7& G+0P$0?+I&R+77+0&$M+0&7=+&0+(,&I(7(%+7&Wai0+(,X&(,%$&$M+0&7=+&%3)7=+7"<&ai%"?@&H)&7="%& :(3&:+&70"+I&7$&+T(?")+&"P&%$?+&$P&7=+&(,1$0"7=?&M(0"(7"$)%&7=(7&G+0P$0?+I&")&(&1$$I& :(3& $M+0& <*00+)7& I(7(.& :$*,I& (,%$& G+0P$0?& ")& (& %"?",(0& :(3& $M+0& (& P*7*0+& %7(7+& $P& a01()"<@iI*)+7@&8%&",,*%70(7+I&")&;(R,+&B.&7=+%+&(,1$0"7=?&M(0"(7"$)%&%++?+I&7$&(,%$& G+0P$0?&")&(&%(7"%P(<7$03&:(3&$M+0&7=+&ai%"?&I(7(@&6$?+&$P&7=+?&%++?&7$&R+&<$??$)& (<0$%%&(,,&I(7(&%+7%.&:"7=&?$%7&G0$?")+)7&R+")1&7=+&PG Cosine Deviation-from-Mean M(0"(7"$)@&&
Table 3.& J+0P$0?()<+& $P& 7$G95& FU;& ()I& 7$G95& '!!& M(0"(7"$)%& $P& ai0+(,& I(7(& %+7& $M+0&7=+&ai%"?&$)+&
Algorithm Similarity Normalization
method AVG Coverage AVG MAE
MNN variations
PG F$%")+& K+M"(7"$)9P0$?9'+()& N-@BBk& L@llAA&
PG i*<,"I"()& 6"?G,+&'+()& N-@BBk& L@lN5N&
CWT variations
PG F$%")+& K+M"(7"$)9P0$?9'+()& A>@`-k& L@l`Ll& PG F$%")+& 6"?G,+&'+()& A>@`-k& L@lN>B&
&
;=+& +TG+0"?+)7(,& ()(,3%"%& $M+0(,,& ")I"<(7+%& 7=(7& 7=+& J/& (,1$0"7=?& <*00+)7,3& "?G,+?+)7+I& ")& 7=+& a01()"<@iI*)+7& G$07(,& "%& %7",,& (& 1$$I& <=$"<+@& n+7.& "7%& +T(<7& G(0(?+7+0"4(7"$)& ()I& P")+97*)")1& %$& 7=(7& 7=+& 0"1=7& M(,*+%& (0+& <=$%+)& 7=(7& :",,& 1"M+& R+77+0& 0+%*,7%.& "%& ()& +T+0<"%+& 7=(7& )++I%& 7$& R+& 7(#")1& G,(<+& S*"7+& $P7+)& ")& %*<=& (& <=()1")1&+)M"0$)?+)7@&8%&7=+&<$??*)"73&$P&*%+0%&10$:%.&7=+&G0$G+07"+%&$P&7=+&e%+0%& T& H7+?%& ?(70"T& W7=(7& "%.& $P& 7=+& I(7(%+7X& :",,& R+& I3)(?"<(,,3& <=()1")1@& Y$0& ")%7()<+.& I*0")1&7=+&G(%7&3+(0&$),3.&?$0+&7=()&-.LLL&)+:&*%+0%&=(M+&0+1"%7+0+I&")&7=+&G$07(,@&H)& (II"7"$).&7=+&<$)7+)7&<$,,+<7"$)%&7$&:="<=&7=+&G$07(,&1"M+%&(<<+%%&7$.&"%&0+(I3&7$&+TG()I& P0$?&(R$*7&--.LLL&"7+?%&7$&%$?+&BL.LLL@&&
;="%& <(,,%& P$0& <(0+P*,& <$)%"I+0(7"$)& ()I& G,())")1& P0$?& 7=+& G+0%G+<7"M+& $P& 7=+& I+%"1)+0& ()I& $G+0(7$0& $P& 7=+& 0+<$??+)I(7"$)& %+0M"<+@& a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
5. Conclusions
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
'()$*%+,"%&+7&(,@.&5L-LX@&H7&1(M+&*%+P*,&")G*7&0+1(0I")1&7=+&"?G0$M+?+)7%&7=(7&)++I&7$& R+&?(I+&")&7=+&(,1$0"7=?&<*00+)7,3&"?G,+?+)7+I&")&a01()"<@iI*)+7@&&
a*0& P*7*0+& :$0#& ")<,*I+%& (& ?$0+& +T7+)%"M+& +TG+0"?+)7& :=+0+& 7=+& <$00+,(7"$)& R+7:++)&7=+&M(0"$*%&(,1$0"7=?"<&G(0(?+7+0%&()I&$G7"$)%&()I&7=+&G0$G+07"+%&$P&7=+&I(7(& %+7%&:",,&R+&+TG,$0+I@&;=+&<*00+)7,3&(M(",(R,+&0+(,&I(7(&%+7%&:",,&R+&*%+I&(%&1+)+0(7$0%& $P&(&,(01+&)*?R+0&$P&%3)7=+7"<&I(7(&%+7%&:"7=&M(03")1&G0$G+07"+%@&;=+)&7=+&CollaFiS %"?*,(7$0&:",,&R+&*%+I&7$&+T+<*7+&(&,(01+&)*?R+0&$P&M(0"(7"$)%&()I&?+(%*0+&=$:&7=+3& G+0P$0?&$M+0&7=+&M(0"$*%&I(7(&%+7%@&8II"7"$)(,&?+70"<%&:",,&(,%$&R+&+)1(1+I.&%*<=&(%& 73G"<(,&$)+%&P$*)I&")&")P$0?(7"$)&0+70"+M(,&W+@1@&J0+<"%"$).&O+<(,,.&Y9?+(%*0+X@&
6. Acknowledgements
;=+& :$0#& G0+%+)7+I& ")& 7="%& G(G+0& =(%& R++)& P*)I+I& :"7=& %*GG$07& R3& 7=+& i*0$G+()& F$??"%%"$).&()I&?$0+&%G+<"P"<(,,3&7=+&YJ>&G0$Q+<7&g(1H!YO8_&8&I(7(&")P0(%70*<7*0+& 7$& %*GG$07& (10"<*,7*0(,& %<"+)7"P"<& <$??*)"7"+%h& $P& 7=+& O+%+(0<=& H)P0(%70*<7*0+%.& F(G(<"7"+%& J0$10(??+.& aRQ+<7"M+& H!YO8& 5L--& -@5@5_& K(7(& ")P0(%70*<7*0+%& P$0& +9 6<"+)<+@& /"$01$%& 2301"(4$%& :(%& (PP","(7+I& :"7=& W()I& P*)I+I& R3X& 810$92)$:& ;+<=)$,$1"+%&(7&7=+&7"?+&7=(7&7="%&%7*I3&7$$#&G,(<+@&
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5@ 8I$?(M"<"*%.& /@.& '()$*%+,"%.& !@.& 2:$)& n@_& '*,7"9F0"7+0"(& O+<$??+)I+0& 63%7+?%@& H)& 2()7$0.&J@.&O"<<".&Y@.&O$#(<=.&d@.&6=(G"0(.&]@&WiI%@X.&O+<$??+)I+0&63%7+?%&b()IR$$#_&8& F$?G,+7+&/*"I+&P$0&O+%+(0<=&6<"+)7"%7%&^&J0(<7"7"$)+0%.&6G0")1+0.&>N`9lLB&W5L--X& B@ ]*I+0.& o@.& 6<=:")I.& F@_& d+(0)")1& :"7=& G+0%$)(,"4+I& 0+<$??+)I+0& %3%7+?%_& 8&
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