9 research outputs found
Optimal Transport Posterior Alignment for Cross-lingual Semantic Parsing
Cross-lingual semantic parsing transfers parsing capability from a
high-resource language (e.g., English) to low-resource languages with scarce
training data. Previous work has primarily considered silver-standard data
augmentation or zero-shot methods, however, exploiting few-shot gold data is
comparatively unexplored. We propose a new approach to cross-lingual semantic
parsing by explicitly minimizing cross-lingual divergence between probabilistic
latent variables using Optimal Transport. We demonstrate how this direct
guidance improves parsing from natural languages using fewer examples and less
training. We evaluate our method on two datasets, MTOP and MultiATIS++SQL,
establishing state-of-the-art results under a few-shot cross-lingual regime.
Ablation studies further reveal that our method improves performance even
without parallel input translations. In addition, we show that our model better
captures cross-lingual structure in the latent space to improve semantic
representation similarity.Comment: Accepted to TACL 2023. Pre-MIT Press publication. 17 pages, 3
figures, 6 table
Extrinsic Evaluation of Machine Translation Metrics
Automatic machine translation (MT) metrics are widely used to distinguish the
translation qualities of machine translation systems across relatively large
test sets (system-level evaluation). However, it is unclear if automatic
metrics are reliable at distinguishing good translations from bad translations
at the sentence level (segment-level evaluation). In this paper, we investigate
how useful MT metrics are at detecting the success of a machine translation
component when placed in a larger platform with a downstream task. We evaluate
the segment-level performance of the most widely used MT metrics (chrF, COMET,
BERTScore, etc.) on three downstream cross-lingual tasks (dialogue state
tracking, question answering, and semantic parsing). For each task, we only
have access to a monolingual task-specific model. We calculate the correlation
between the metric's ability to predict a good/bad translation with the
success/failure on the final task for the Translate-Test setup. Our experiments
demonstrate that all metrics exhibit negligible correlation with the extrinsic
evaluation of the downstream outcomes. We also find that the scores provided by
neural metrics are not interpretable mostly because of undefined ranges. We
synthesise our analysis into recommendations for future MT metrics to produce
labels rather than scores for more informative interaction between machine
translation and multilingual language understanding.Comment: ACL 2023 Camera Read
On the Impact of Fixed Point Hardware for Optical Fiber Nonlinearity Compensation Algorithms
Nonlinearity mitigation using digital signal processing has been shown to
increase the achievable data rates of optical fiber transmission links. One
especially effective technique is digital back propagation (DBP), an algorithm
capable of simultaneously compensating for linear and nonlinear channel
distortions. The most significant barrier to implementing this technique,
however, is its high computational complexity. In recent years, there have been
several proposed alternatives to DBP with reduced computational complexity,
although such techniques have not demonstrated performance benefits
commensurate with the complexity of implementation. In order to fully
characterize the computational requirements of DBP, there is a need to model
the algorithm behavior when constrained to the logic used in a digital coherent
receiver. Such a model allows for the analysis of any signal recovery algorithm
in terms of true hardware complexity which, crucially, includes the bit-depth
of the multiplication operation. With a limited bit depth, there is
quantization noise, introduced with each arithmetic operation, and it can no
longer be assumed that the conventional DBP algorithm will outperform its low
complexity alternatives. In this work, DBP and a single nonlinear step DBP
implementation, the \textit{Enhanced Split Step Fourier} method (ESSFM), were
compared with linear equalization using a generic software model of fixed point
hardware. The requirements of bit depth and fast Fourier transform (FFT) size
are discussed to examine the optimal operating regimes for these two schemes of
digital nonlinearity compensation. For a 1000 km transmission system, it was
found that (assuming an optimized FFT size), in terms of SNR, the ESSFM
algorithm outperformed the conventional DBP for all hardware resolutions up to
13 bits.Comment: 8 pages, 8 figures, journal submissio
Ground- and Excited-State Electronic Structure of an emissive pyrazine-bridged Ruthenium (II) dinuclear complex
The synthesis, characterization, and electrochemical, photophysical, and photochemical properties of the binuclear compounds [(Ru(H8-bpy)2)2((Metr)2Pz)](PF6)2 and [(Ru(D8-bpy)2)2((Metr)2Pz)](PF6)2, where bpy is 2,2'-bipyridine and H2(Metr)2Pz is the planar ligand 2,5-bis(5'-methyl-4'H-[1,2,4]triaz-3'-yl)pyrazine, are reported. Electrochemical and spectro-electrochemical investigations indicate that the ground-state interaction between each metal center is predominantly electrostatic and in the mixed-valence form only a low level of ground-state delocalization is present. Resonance Raman, transient, and time-resolved spectroscopies enable a detailed assignment to be made of the excited-state photophysical properties of the complexes. Deuteriation is employed to both facilitate spectroscopic characterization and investigate the nature of the lowest excited states.