15 research outputs found
Uniquely pairable graphs
AbstractThe concept of a k-pairable graph was introduced by Z. Chen [On k-pairable graphs, Discrete Mathematics 287 (2004), 11–15] as an extension of hypercubes and graphs with an antipodal isomorphism. In the present paper we generalize further this concept of a k-pairable graph to the concept of a semi-pairable graph. We prove that a graph is semi-pairable if and only if its prime factor decomposition contains a semi-pairable prime factor or some repeated prime factors. We also introduce a special class of k-pairable graphs which are called uniquely k-pairable graphs. We show that a graph is uniquely pairable if and only if its prime factor decomposition has at least one pairable prime factor, each prime factor is either uniquely pairable or not semi-pairable, and all prime factors which are not semi-pairable are pairwise non-isomorphic. As a corollary we give a characterization of uniquely pairable Cartesian product graphs
Outerplane bipartite graphs with isomorphic resonance graphs
We present novel results related to isomorphic resonance graphs of
2-connected outerplane bipartite graphs. As the main result, we provide a
structure characterization for 2-connected outerplane bipartite graphs with
isomorphic resonance graphs. Moreover, two additional characterizations are
expressed in terms of resonance digraphs and via local structures of inner
duals of 2-connected outerplane bipartite graphs, respectively
Resonance graphs of plane bipartite graphs as daisy cubes
We characterize all plane bipartite graphs whose resonance graphs are daisy
cubes and therefore generalize related results on resonance graphs of benzenoid
graphs, catacondensed even ring systems, as well as 2-connected outerplane
bipartite graphs. Firstly, we prove that if is a plane elementary bipartite
graph other than , then the resonance graph is a daisy cube if and
only if the Fries number of equals the number of finite faces of , which
in turn is equivalent to being homeomorphically peripheral color
alternating. Next, we extend the above characterization from plane elementary
bipartite graphs to all plane bipartite graphs and show that the resonance
graph of a plane bipartite graph is a daisy cube if and only if is
weakly elementary bipartite and every elementary component of other than
is homeomorphically peripheral color alternating. Along the way, we prove
that a Cartesian product graph is a daisy cube if and only if all of its
nontrivial factors are daisy cubes
Style-Label-Free: Cross-Speaker Style Transfer by Quantized VAE and Speaker-wise Normalization in Speech Synthesis
Cross-speaker style transfer in speech synthesis aims at transferring a style
from source speaker to synthesised speech of a target speaker's timbre. Most
previous approaches rely on data with style labels, but manually-annotated
labels are expensive and not always reliable. In response to this problem, we
propose Style-Label-Free, a cross-speaker style transfer method, which can
realize the style transfer from source speaker to target speaker without style
labels. Firstly, a reference encoder structure based on quantized variational
autoencoder (Q-VAE) and style bottleneck is designed to extract discrete style
representations. Secondly, a speaker-wise batch normalization layer is proposed
to reduce the source speaker leakage. In order to improve the style extraction
ability of the reference encoder, a style invariant and contrastive data
augmentation method is proposed. Experimental results show that the method
outperforms the baseline. We provide a website with audio samples.Comment: Published to ISCSLP 202
Improving Prosody for Cross-Speaker Style Transfer by Semi-Supervised Style Extractor and Hierarchical Modeling in Speech Synthesis
Cross-speaker style transfer in speech synthesis aims at transferring a style
from source speaker to synthesized speech of a target speaker's timbre. In most
previous methods, the synthesized fine-grained prosody features often represent
the source speaker's average style, similar to the one-to-many problem(i.e.,
multiple prosody variations correspond to the same text). In response to this
problem, a strength-controlled semi-supervised style extractor is proposed to
disentangle the style from content and timbre, improving the representation and
interpretability of the global style embedding, which can alleviate the
one-to-many mapping and data imbalance problems in prosody prediction. A
hierarchical prosody predictor is proposed to improve prosody modeling. We find
that better style transfer can be achieved by using the source speaker's
prosody features that are easily predicted. Additionally, a
speaker-transfer-wise cycle consistency loss is proposed to assist the model in
learning unseen style-timbre combinations during the training phase.
Experimental results show that the method outperforms the baseline. We provide
a website with audio samples.Comment: Accepted by ICASSP202
Forcing faces in plane bipartite graphs
AbstractLet Ω denote the class of connected plane bipartite graphs with no pendant edges. A finite face s of a graph G∈Ω is said to be a forcing face of G if the subgraph of G obtained by deleting all vertices of s together with their incident edges has exactly one perfect matching. This is a natural generalization of the concept of forcing hexagons in a hexagonal system introduced in Che and Chen [Forcing hexagons in hexagonal systems, MATCH Commun. Math. Comput. Chem. 56 (3) (2006) 649–668]. We prove that any connected plane bipartite graph with a forcing face is elementary. We also show that for any integers n and k with n⩾4 and n⩾k⩾0, there exists a plane elementary bipartite graph such that exactly k of the n finite faces of G are forcing. We then give a shorter proof for a recent result that a connected cubic plane bipartite graph G has at least two disjoint M-resonant faces for any perfect matching M of G, which is a main theorem in the paper [S. Bau, M.A. Henning, Matching transformation graphs of cubic bipartite plane graphs, Discrete Math. 262 (2003) 27–36]. As a corollary, any connected cubic plane bipartite graph has no forcing faces. Using the tool of Z-transformation graphs developed by Zhang et al. [Z-transformation graphs of perfect matchings of hexagonal systems, Discrete Math. 72 (1988) 405–415; Plane elementary bipartite graphs, Discrete Appl. Math. 105 (2000) 291–311], we characterize the plane elementary bipartite graphs whose finite faces are all forcing. We also obtain a necessary and sufficient condition for a finite face in a plane elementary bipartite graph to be forcing, which enables us to investigate the relationship between the existence of a forcing edge and the existence of a forcing face in a plane elementary bipartite graph, and find out that the former implies the latter but not vice versa. Moreover, we characterize the plane bipartite graphs that can be turned to have all finite faces forcing by subdivisions