3,143 research outputs found
A Framework for Globally Optimizing Mixed-Integer Signomial Programs
Mixed-integer signomial optimization problems have broad applicability in engineering. Extending the Global Mixed-Integer Quadratic Optimizer, GloMIQO (Misener, Floudas in J. Glob. Optim., 2012. doi:10.1007/s10898-012-9874-7), this manuscript documents a computational framework for deterministically addressing mixed-integer signomial optimization problems to ε-global optimality. This framework generalizes the GloMIQO strategies of (1) reformulating user input, (2) detecting special mathematical structure, and (3) globally optimizing the mixed-integer nonconvex program. Novel contributions of this paper include: flattening an expression tree towards term-based data structures; introducing additional nonconvex terms to interlink expressions; integrating a dynamic implementation of the reformulation-linearization technique into the branch-and-cut tree; designing term-based underestimators that specialize relaxation strategies according to variable bounds in the current tree node. Computational results are presented along with comparison of the computational framework to several state-of-the-art solvers. © 2013 Springer Science+Business Media New York
Distributed Robustness Analysis of Interconnected Uncertain Systems Using Chordal Decomposition
Large-scale interconnected uncertain systems commonly have large state and
uncertainty dimensions. Aside from the heavy computational cost of solving
centralized robust stability analysis techniques, privacy requirements in the
network can also introduce further issues. In this paper, we utilize IQC
analysis for analyzing large-scale interconnected uncertain systems and we
evade these issues by describing a decomposition scheme that is based on the
interconnection structure of the system. This scheme is based on the so-called
chordal decomposition and does not add any conservativeness to the analysis
approach. The decomposed problem can be solved using distributed computational
algorithms without the need for a centralized computational unit. We further
discuss the merits of the proposed analysis approach using a numerical
experiment.Comment: 3 figures. Submitted to the 19th IFAC world congres
Distributed Robust Stability Analysis of Interconnected Uncertain Systems
This paper considers robust stability analysis of a large network of
interconnected uncertain systems. To avoid analyzing the entire network as a
single large, lumped system, we model the network interconnections with
integral quadratic constraints. This approach yields a sparse linear matrix
inequality which can be decomposed into a set of smaller, coupled linear matrix
inequalities. This allows us to solve the analysis problem efficiently and in a
distributed manner. We also show that the decomposed problem is equivalent to
the original robustness analysis problem, and hence our method does not
introduce additional conservativeness.Comment: This paper has been accepted for presentation at the 51st IEEE
Conference on Decision and Control, Maui, Hawaii, 201
Morphological Analysis as Classification: an Inductive-Learning Approach
Morphological analysis is an important subtask in text-to-speech conversion,
hyphenation, and other language engineering tasks. The traditional approach to
performing morphological analysis is to combine a morpheme lexicon, sets of
(linguistic) rules, and heuristics to find a most probable analysis. In
contrast we present an inductive learning approach in which morphological
analysis is reformulated as a segmentation task. We report on a number of
experiments in which five inductive learning algorithms are applied to three
variations of the task of morphological analysis. Results show (i) that the
generalisation performance of the algorithms is good, and (ii) that the lazy
learning algorithm IB1-IG performs best on all three tasks. We conclude that
lazy learning of morphological analysis as a classification task is indeed a
viable approach; moreover, it has the strong advantages over the traditional
approach of avoiding the knowledge-acquisition bottleneck, being fast and
deterministic in learning and processing, and being language-independent.Comment: 11 pages, 5 encapsulated postscript figures, uses non-standard NeMLaP
proceedings style nemlap.sty; inputs ipamacs (international phonetic
alphabet) and epsf macro
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