arXiv subjects

Liang Qiu

Publications and source records attributed to Liang Qiu.

42 records · Page 3Linked to original sources

arXiv2020

Vertical-Horizontal Structured Attention for Generating Music with Chords

In this paper, we propose a lightweight music-generating model based on variational autoencoder (VAE) with structured attention. Generating music is different from generating text because the melodies with chords give listeners distinguished polyphonic feelings. In a piece of music, a chord consisting of multiple notes comes from either the mixture of multiple instruments or the combination of multiple keys of a single instrument. We focus our study on the latter. Our model captures not only the temporal relations along time but the structure relations between keys. Experimental results show that our model has a better performance than baseline MusicVAE in capturing notes in a chord. Besides, our method accords with music theory since it maintains the configuration of the circle of fifths, distinguishes major and minor keys from interval vectors, and manifests meaningful structures between music phrases.

cs.SD↗

arXiv2020

Structured Attention for Unsupervised Dialogue Structure Induction

Inducing a meaningful structural representation from one or a set of dialogues is a crucial but challenging task in computational linguistics. Advancement made in this area is critical for dialogue system design and discourse analysis. It can also be extended to solve grammatical inference. In this work, we propose to incorporate structured attention layers into a Variational Recurrent Neural Network (VRNN) model with discrete latent states to learn dialogue structure in an unsupervised fashion. Compared to a vanilla VRNN, structured attention enables a model to focus on different parts of the source sentence embeddings while enforcing a structural inductive bias. Experiments show that on two-party dialogue datasets, VRNN with structured attention learns semantic structures that are similar to templates used to generate this dialogue corpus. While on multi-party dialogue datasets, our model learns an interactive structure demonstrating its capability of distinguishing speakers or addresses, automatically disentangling dialogues without explicit human annotation.

cs.CL↗

arXiv2018

Recurrent Neural Networks with Pre-trained Language Model Embedding for Slot Filling Task

In recent years, Recurrent Neural Networks (RNNs) based models have been applied to the Slot Filling problem of Spoken Language Understanding and achieved the state-of-the-art performances. In this paper, we investigate the effect of incorporating pre-trained language models into RNN based Slot Filling models. Our evaluation on the Airline Travel Information System (ATIS) data corpus shows that we can significantly reduce the size of labeled training data and achieve the same level of Slot Filling performance by incorporating extra word embedding and language model embedding layers pre-trained on unlabeled corpora.

cs.CL↗

arXiv2017

Bounds on skew information and local quantum uncertainty for state conversion

We establish strict upper bounds on local quantum uncertainty (LQU) and skew information associated with state conversion via certain quantum channels. Specifically, we obtain a bound on the achievable LQU for bipartite channels whose Kraus operators commute with nondegenerate von Neumann measurements on the first subsystem, and this LQU bound is expressed in terms of the skew information for the first subsystem. Furthermore, we establish a bound on the skew information of one subsystem obtained from any initial bipartite state subject to any quantum steering channel, and this bound is expressed in terms of the LQU for the initial joint-system state. Our two claims show that state conversion has fundamental limitations relating LQU with skew information.

quant-ph↗

arXiv2016

Thermoelectric properties of topological insulator $\mathrm{BaSn_2}$

Recently, $\mathrm{BaSn_2}$ is predicted to be a strong topological insulator by the first-principle calculations. It is well known that topological insulator has a close connection to thermoelectric material, such as $\mathrm{Bi_2Te_3}$ family. In this work, we investigate thermoelectric properties of $\mathrm{BaSn_2}$ by the first-principles combined with Boltzmann transport theory. The electronic part is carried out by a modified Becke and Johnson (mBJ) exchange potential, including spin-orbit coupling (SOC), while the phonon part is performed using generalized gradient approximation (GGA). It is found that the electronic transport coefficients between the in-plane and cross-plane directions show the strong anisotropy, while lattice lattice thermal conductivities show an almost isotropy. Calculated results show a very low lattice thermal conductivity for $\mathrm{BaSn_2}$, and the corresponding average lattice thermal conductivity at room temperature is 1.69 $\mathrm{W m^{-1} K^{-1}}$, which is comparable or lower than those of lead chalcogenides and bismuth-tellurium systems as classic thermoelectric materials. Due to the complicated scattering mechanism, calculating scattering time $τ$ is challenging. By using a empirical $τ$=$10^{-14}$ s, the n-type figure of merit $ZT$ is greater than 0.40 in wide temperature range. Experimentally, it is possible to attain better thermoelectric performance, or to enhance one by strain or tuning size parameter. This work indicates that $\mathrm{BaSn_2}$ may be a potential thermoelectric material, which can stimulate further theoretical and experimental works.

cond-mat.mtrl-sci↗

arXiv2007

Scheme for remote implementation of partially unknown quantum operation of two qubits in cavity QED

By constructing the recovery operations of the protocol of remote implementation of partially unknown quantum operation of two qubits [An Min Wang: PRA, \textbf{74}, 032317(2006)], we present a scheme to implement it in cavity QED. Long-lived Rydberg atoms are used as qubits, and the interaction between the atoms and the field of cavity is a nonresonant one. Finally, we analyze the experimental feasibility of this scheme.

quant-ph↗