Title
A simple iterative approach to parameter optimization.
Abstract
Various bioinformatics problems require optimizing several different properties simultaneously. For example, in the protein threading problem, a scoring function combines the values for different parameters of possible sequence-to-structure alignments into a single score to allow for unambiguous optimization. In this context, an essential question is how each property should be weighted. As the native structures are known for some sequences, a partial ordering on optimal alignments to other structures, e.g., derived from structural comparisons, may be used to adjust the weights. To resolve the arising interdependence of weights and computed solutions, we propose a heuristic approach: iterating the computation of solutions (here, threading alignments) given the weights and the estimation of optimal weights of the scoring function given these solutions via systematic calibration methods. For our application (i.e., threading), this iterative approach results in structurally meaningful weights that significantly improve performance on both the training and the test data sets. In addition, the optimized parameters show significant improvements on the recognition rate for a grossly enlarged comprehensive benchmark, a modified recognition protocol as well as modified alignment types (local instead of global and profiles instead of single sequences). These results show the general validity of the optimized weights for the given threading program and the associated scoring contributions.
Year
DOI
Venue
2000
10.1089/106652700750050907
Journal of Computational Biology
Keywords
DocType
Volume
computed solution,comprehensive test data,linear scoring function,different way,threading alignment,improved performance,optimal weight,scoring function,simple iterative approach,optimal alignment,different property,score function,fold recognition,structure alignment,energy minimization,nmr,partial order,protein threading
Conference
7
Issue
ISSN
ISBN
3-4
1066-5277
1-58113-186-0
Citations 
PageRank 
References 
10
1.07
5
Authors
3
Name
Order
Citations
PageRank
Alexander Zien11255146.93
Ralf Zimmer2101.07
Thomas Lengauer33155605.03