Structural Identifiability in Low-Rank Matrix Factorization
In many signal processing and data mining applications, we need to approximate a given matrix Y with a low-rank product Y ≈ AX . Both matrices A and X are to be determined, but we assume that from the specifics of the application we have an important piece of a-priori knowledge: A must have zeros at...
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| Vydáno v: | Algorithmica Ročník 56; číslo 3; s. 313 - 332 |
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| Hlavní autoři: | , , , |
| Médium: | Journal Article |
| Jazyk: | angličtina |
| Vydáno: |
New York
Springer-Verlag
01.03.2010
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| Témata: | |
| ISSN: | 0178-4617, 1432-0541 |
| On-line přístup: | Získat plný text |
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| Shrnutí: | In many signal processing and data mining applications, we need to approximate a given matrix
Y
with a low-rank product
Y
≈
AX
. Both matrices
A
and
X
are to be determined, but we assume that from the specifics of the application we have an important piece of a-priori knowledge:
A
must have zeros at certain positions.
In general, different
AX
factorizations approximate a given
Y
equally well, so a fundamental question is whether the known zero pattern of
A
contributes to the uniqueness of the factorization. Using the notion of structural rank, we present a combinatorial characterization of uniqueness up to diagonal scaling (subject to a mild non-degeneracy condition on the factors), called structural identifiability of the model.
Next, we define an optimization problem that arises in the need for efficient experimental design. In this context,
Y
contains sensor measurements over several time samples,
X
contains source signals over time samples and
A
contains the source-sensor mixing coefficients. Our task is to monitor the signal sources with the cheapest subset of sensors, while maintaining structural identifiability. Firstly, we show that this problem is NP-hard. Secondly, we present a mixed integer linear program for its exact solution together with two practical incremental approaches. We also propose a greedy approximation algorithm. Finally, we perform computational experiments on simulated problem instances of various sizes. |
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| ISSN: | 0178-4617 1432-0541 |
| DOI: | 10.1007/s00453-009-9331-2 |