Non-negative matrix factorization as a feature selection tool for maximum margin classifiers
AssigneeSeiko Epson Corporation
InventorsMithun Das Gupta, Jing Xiao
Life of this patent
Estimating the term…
Abstract
Non-negative matrix factorization, NMF, is combined with identification of a maximum margin classifier by minimizing a cost function that contains a generative component and the discriminative component. The relative weighting between the generative component and the discriminative component are adjusting during subsequent iterations such that initially, when confidence is low, the generative model is favored. But as the iterations proceed, confidence increases and the weight of the discriminative component is steadily increased until it is of equal weight as the generative model. Preferably, the cost function to be minimized is: min F , G ≥ 0 X - FG 2 + γ ( w 2 + C ∑ i = 1 n L ( y i , w · g i + b ) ) .
Claims16
A method of decomposing a given matrix vector X into two matrix vectors, F and G, comprising:
- providing a data processing device to implement the following steps:
- minimizing a cost function that combine a non-negative matrix factorization, NMF and maximum margin classifier satisfying the following relationship:
- min
- F
- ,
- G
- ≥
- 0
-
-
- X
- -
- FG
-
- 2
- +
- γ
-
- (
-
- w
-
- 2
- +
- C
-
- ∑
- i
- =
- 1
- n
-
- L
-
- (
- y
- i
- ,
- w
- ·
- g
- i
- +
- b
- )
- )
- wherein:
- X∈;
- F∈;
- G∈;
- w∈;
- yi∈{−1,1}∀i;
- gi∈ is the ith column of G;
- symbol (.) represents the dot product of the two vectors;
- L(y,t) is a loss function where t=(w.gi+b), and L(y,t)=max(0,1−yt)p;
- and
- γ is a constant that distributes the relative importance of the two terms in the optimization;
- wherein minimizing the cost function is achieved h successive iterations and γ is the relative between the generative component and the discriminative component of the cost function, γ ranges from 0 to 1 and is increased incrementally during each iteration;
- and
- wherein during each of said iterations, F is updated by the following relationship:
- F
- n
- +
- 1
- =
- F
- n
- ·
- XG
- T
- (
- FG
- )
-
- G
- T
- .
A method for applying non-negative matrix factorization, NMF, decomposition to a given matrix X to produce factorizing matrices F and G, comprising the following steps:
- providing a data processing device to implement the following steps:
- (a) updating F, where
- F
- n
- +
- 1
- =
- F
- n
- ·
- XG
- T
- (
- FG
- )
-
- G
- T
- ;
- (b) updating G, where
- G
- k
- +
- 1
- =
- G
- k
- ·
- (
- F
- T
-
- X
- +
- γ
-
- (
- G
- k
-
- diag
-
- (
- (
- 1
- +
- λ
- )
-
- β
- 2
- +
- L
- 2
- )
- -
- G
- k
-
- [
- β
- ·
- (
- β
-
- λ
- 2
- +
- L
- )
- ]
-
- 1
- T
- -
- (
- G
- k
-
- β
- )
-
- [
- L
- +
- λ
- 2
-
- β
- ]
- T
- )
- )
- (
- (
- F
- T
-
- F
- )
-
- g
- k
- i
- +
- γ
-
- (
- G
- k
-
- diag
-
- (
- (
- 1
- +
- λ
- )
-
- β
- 2
- +
- L
- 2
- )
- )
- )
- (c) updating a matrix K such that K←G′G;
- (d) updating first memory location new_sv, using the following relation:
- new_sv←{1, 2, . . . , n};
- e) updating second memory location old_sv, using the following relation:
- old_sv←new_sv;
- (f) updating a vector β, where [βT β0]←M−1[Yold—svT0]T;
- (g) updating first memory location new_sv, using the following relation:
- new_sv←indices i, where yi(Kβ)i<1;
- and
- (h) repeating steps (e) through (g) until old_sv=new—sv;
- wherein the above steps incorporate identification of a maximum margin classifier to the NMF decomposition process.
Dependencies are inferred from the claim text.