3,443 research outputs found
Distributed Stochastic Optimization under Imperfect Information
We consider a stochastic convex optimization problem that requires minimizing
a sum of misspecified agentspecific expectation-valued convex functions over
the intersection of a collection of agent-specific convex sets. This
misspecification is manifested in a parametric sense and may be resolved
through solving a distinct stochastic convex learning problem. Our interest
lies in the development of distributed algorithms in which every agent makes
decisions based on the knowledge of its objective and feasibility set while
learning the decisions of other agents by communicating with its local
neighbors over a time-varying connectivity graph. While a significant body of
research currently exists in the context of such problems, we believe that the
misspecified generalization of this problem is both important and has seen
little study, if at all. Accordingly, our focus lies on the simultaneous
resolution of both problems through a joint set of schemes that combine three
distinct steps: (i) An alignment step in which every agent updates its current
belief by averaging over the beliefs of its neighbors; (ii) A projected
(stochastic) gradient step in which every agent further updates this averaged
estimate; and (iii) A learning step in which agents update their belief of the
misspecified parameter by utilizing a stochastic gradient step. Under an
assumption of mere convexity on agent objectives and strong convexity of the
learning problems, we show that the sequences generated by this collection of
update rules converge almost surely to the solution of the correctly specified
stochastic convex optimization problem and the stochastic learning problem,
respectively
Handwritten Character Recognition of South Indian Scripts: A Review
Handwritten character recognition is always a frontier area of research in
the field of pattern recognition and image processing and there is a large
demand for OCR on hand written documents. Even though, sufficient studies have
performed in foreign scripts like Chinese, Japanese and Arabic characters, only
a very few work can be traced for handwritten character recognition of Indian
scripts especially for the South Indian scripts. This paper provides an
overview of offline handwritten character recognition in South Indian Scripts,
namely Malayalam, Tamil, Kannada and Telungu.Comment: Paper presented on the "National Conference on Indian Language
Computing", Kochi, February 19-20, 2011. 6 pages, 5 figure
Relationship between Ultrasonic Pulse Velocity and Compressive Strength of Self Compacting Concrete incorporate Rice Husk Ash and Metakaolin
The objective of the present investigation was to evaluate RHA and MK as supplementary cementitious materials (in both binary and ternary systems) in terms of harden properties in blended cement SCC and to identify the optimal level of replacement of ordinary Portland cement (OPC) with RHA, MK, or RHA+MK. The blended cements were prepared by replacing OPC with RHA, MK, or RHA+MK (5ndash40%) in dry conditions. In addition to that the interrelationship between harden properties such as compressive strength and ultrasonic pulse velocity was discussed
Ordinal invariants in topology - summary
This article does not have an abstract
Sets of periods of dynamical systems
In this article, we present a coherent, though not exhaustive, account of some well-known and some recent results of many mathematicians (including our own) on the following question: Given a "nice" class of dynamical systems, which subsets of N arise as the sets of periods of members of that class? While stating and explaining some elegant answers, proofs have been outlined or indicated occasionally
Morphological filtering on hypergraphs
The focus of this article is to develop computationally efficient
mathematical morphology operators on hypergraphs. To this aim we consider
lattice structures on hypergraphs on which we build morphological operators. We
develop a pair of dual adjunctions between the vertex set and the hyper edge
set of a hypergraph H, by defining a vertex-hyperedge correspondence. This
allows us to recover the classical notion of a dilation/erosion of a subset of
vertices and to extend it to subhypergraphs of H. Afterward, we propose several
new openings, closings, granulometries and alternate sequential filters acting
(i) on the subsets of the vertex and hyperedge set of H and (ii) on the
subhypergraphs of a hypergraph
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