108 research outputs found
Interval non-edge-colorable bipartite graphs and multigraphs
An edge-coloring of a graph with colors is called an interval
-coloring if all colors are used, and the colors of edges incident to any
vertex of are distinct and form an interval of integers. In 1991 Erd\H{o}s
constructed a bipartite graph with 27 vertices and maximum degree 13 which has
no interval coloring. Erd\H{o}s's counterexample is the smallest (in a sense of
maximum degree) known bipartite graph which is not interval colorable. On the
other hand, in 1992 Hansen showed that all bipartite graphs with maximum degree
at most 3 have an interval coloring. In this paper we give some methods for
constructing of interval non-edge-colorable bipartite graphs. In particular, by
these methods, we construct three bipartite graphs which have no interval
coloring, contain 20,19,21 vertices and have maximum degree 11,12,13,
respectively. This partially answers a question that arose in [T.R. Jensen, B.
Toft, Graph coloring problems, Wiley Interscience Series in Discrete
Mathematics and Optimization, 1995, p. 204]. We also consider similar problems
for bipartite multigraphs.Comment: 18 pages, 7 figure
Constructions of skew-tolerant and skew-detecting codes
The paradigm of skew-tolerant parallel asynchronous communication was introduced by Blaum and Bruck (see ibid., vol. 39, 1993) along with constructions for codes that can tolerate or detect skew. Some of these constructions were improved by Khachatrian (1991). In this paper these constructions are improved upon further, and the authors prove that the new constructions are, in a certain sense, optimal
On q-ary codes correcting all unidirectional errors of a limited magnitude
We consider codes over the alphabet Q={0,1,..,q-1}intended for the control of
unidirectional errors of level l. That is, the transmission channel is such
that the received word cannot contain both a component larger than the
transmitted one and a component smaller than the transmitted one. Moreover, the
absolute value of the difference between a transmitted component and its
received version is at most l.
We introduce and study q-ary codes capable of correcting all unidirectional
errors of level l. Lower and upper bounds for the maximal size of those codes
are presented.
We also study codes for this aim that are defined by a single equation on the
codeword coordinates(similar to the Varshamov-Tenengolts codes for correcting
binary asymmetric errors). We finally consider the problem of detecting all
unidirectional errors of level l.Comment: 22 pages,no figures. Accepted for publication of Journal of Armenian
Academy of Sciences, special issue dedicated to Rom Varshamo
Identifying and Disentangling Spurious Features in Pretrained Image Representations
Neural networks employ spurious correlations in their predictions, resulting
in decreased performance when these correlations do not hold. Recent works
suggest fixing pretrained representations and training a classification head
that does not use spurious features. We investigate how spurious features are
represented in pretrained representations and explore strategies for removing
information about spurious features. Considering the Waterbirds dataset and a
few pretrained representations, we find that even with full knowledge of
spurious features, their removal is not straightforward due to entangled
representation. To address this, we propose a linear autoencoder training
method to separate the representation into core, spurious, and other features.
We propose two effective spurious feature removal approaches that are applied
to the encoding and significantly improve classification performance measured
by worst group accuracy
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Effect of halogen substitution on the enthalpies of solvation and hydrogen bonding of organic solutes in chlorobenzene and 1,2-dichlorobenzene derived using multi-parameter correlations
Article on the effect of halogen substitution on the enthalpies of solvation and hydrogen bonding of organic solutes in chlorobenzene and 1,2-dichlorobenzene derived using multi-parameter correlations
Track D Social Science, Human Rights and Political Science
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd
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