9,161 research outputs found
Quadratic Projection Based Feature Extraction with Its Application to Biometric Recognition
This paper presents a novel quadratic projection based feature extraction
framework, where a set of quadratic matrices is learned to distinguish each
class from all other classes. We formulate quadratic matrix learning (QML) as a
standard semidefinite programming (SDP) problem. However, the con- ventional
interior-point SDP solvers do not scale well to the problem of QML for
high-dimensional data. To solve the scalability of QML, we develop an efficient
algorithm, termed DualQML, based on the Lagrange duality theory, to extract
nonlinear features. To evaluate the feasibility and effectiveness of the
proposed framework, we conduct extensive experiments on biometric recognition.
Experimental results on three representative biometric recogni- tion tasks,
including face, palmprint, and ear recognition, demonstrate the superiority of
the DualQML-based feature extraction algorithm compared to the current
state-of-the-art algorithm
SAT Modulo Monotonic Theories
We define the concept of a monotonic theory and show how to build efficient
SMT (SAT Modulo Theory) solvers, including effective theory propagation and
clause learning, for such theories. We present examples showing that monotonic
theories arise from many common problems, e.g., graph properties such as
reachability, shortest paths, connected components, minimum spanning tree, and
max-flow/min-cut, and then demonstrate our framework by building SMT solvers
for each of these theories. We apply these solvers to procedural content
generation problems, demonstrating major speed-ups over state-of-the-art
approaches based on SAT or Answer Set Programming, and easily solving several
instances that were previously impractical to solve
Coupling problem in thermal systems simulations
Building energy simulation is playing a key role in building design in order to reduce the energy
consumption and, consequently, the CO2 emissions. An object-oriented tool called NEST
is used to simulate all the phenomena that appear in a building. In the case of energy and momentum
conservation and species transport, the current solver behaves well, but in the case of
mass conservation it takes a lot of time to reach a solution. For this reason, in this work, instead
of solving the continuity equations explicitly, an implicit method based on the Trust Region algorithm
is proposed. Previously, a study of the properties of the model used by NEST-Building
software has been done in order to simplify the requirements of the solver. For a building with
only 9 rooms the new solver is a thousand times faster than the current method
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