110 research outputs found
Learning an Effective Context-Response Matching Model with Self-Supervised Tasks for Retrieval-based Dialogues
Building an intelligent dialogue system with the ability to select a proper
response according to a multi-turn context is a great challenging task.
Existing studies focus on building a context-response matching model with
various neural architectures or PLMs and typically learning with a single
response prediction task. These approaches overlook many potential training
signals contained in dialogue data, which might be beneficial for context
understanding and produce better features for response prediction. Besides, the
response retrieved from existing dialogue systems supervised by the
conventional way still faces some critical challenges, including incoherence
and inconsistency. To address these issues, in this paper, we propose learning
a context-response matching model with auxiliary self-supervised tasks designed
for the dialogue data based on pre-trained language models. Specifically, we
introduce four self-supervised tasks including next session prediction,
utterance restoration, incoherence detection and consistency discrimination,
and jointly train the PLM-based response selection model with these auxiliary
tasks in a multi-task manner. By this means, the auxiliary tasks can guide the
learning of the matching model to achieve a better local optimum and select a
more proper response. Experiment results on two benchmarks indicate that the
proposed auxiliary self-supervised tasks bring significant improvement for
multi-turn response selection in retrieval-based dialogues, and our model
achieves new state-of-the-art results on both datasets.Comment: 10 page
Preparation of graphene film reinforced CoCrFeNiMn high-entropy alloy matrix composites with strength-plasticity synergy via flake powder metallurgy method
Inspired by the design principle of pearl structure, a bottom-up flake powder self-assembly arrangement strategy, flake powder metallurgy, is used to prepare graphene films (GFs) reinforced CoCrFeNiMn high-entropy alloy (HEA) matrix composites with a pearl laminated structure. Flaky HEA powder was prepared by ball milling method and homogeneously mixed with Ni plated GFs. Vacuum hot-press sintering (VHPS) technique was carried out to solidify the mixed powders to obtain composites with uniform distribution of GFs(Ni) and flaky HEA. The results show that the bottom-up preparation strategy can effectively fabricate bionic laminated HEA matrix composites, and the composites have a distinct pearly laminated structure. The tensile strength of the composites with 5 vol% GFs(Ni) content reached 834.04 MPa, and the elongation reached 26.58 %. The compressive strength in parallel and perpendicular laminar directions reached 2069.66 MPa and 2418.45 MPa at 50 % strain, respectively. The laminated GFs(Ni)/HEA matrix composites possessed excellent strength and maintained good plasticity. In this study, the strengthening and toughening mechanism of the laminated GFs(Ni)/HEA matrix composites is discussed in detail, and the results show that the laminated structure and GFs(Ni) are favorable for the hardening and strengthening of the HEA matrix
WizardLM: Empowering Large Language Models to Follow Complex Instructions
Training large language models (LLM) with open-domain instruction following
data brings colossal success. However, manually creating such instruction data
is very time-consuming and labor-intensive. Moreover, humans may struggle to
produce high-complexity instructions. In this paper, we show an avenue for
creating large amounts of instruction data with varying levels of complexity
using LLM instead of humans. Starting with an initial set of instructions, we
use our proposed Evol-Instruct to rewrite them step by step into more complex
instructions. Then, we mix all generated instruction data to fine-tune LLaMA.
We call the resulting model WizardLM. Human evaluations on a
complexity-balanced test bed show that instructions from Evol-Instruct are
superior to human-created ones. By analyzing the human evaluation results of
the high complexity part, we demonstrate that outputs from our WizardLM model
are preferred to outputs from OpenAI ChatGPT. Even though WizardLM still lags
behind ChatGPT in some aspects, our findings suggest that fine-tuning with
AI-evolved instructions is a promising direction for enhancing large language
models. Our codes and generated data are public at
https://github.com/nlpxucan/WizardLMComment: large language model, instruction fine-tun
LexMAE: Lexicon-Bottlenecked Pretraining for Large-Scale Retrieval
In large-scale retrieval, the lexicon-weighting paradigm, learning weighted
sparse representations in vocabulary space, has shown promising results with
high quality and low latency. Despite it deeply exploiting the
lexicon-representing capability of pre-trained language models, a crucial gap
remains between language modeling and lexicon-weighting retrieval -- the former
preferring certain or low-entropy words whereas the latter favoring pivot or
high-entropy words -- becoming the main barrier to lexicon-weighting
performance for large-scale retrieval. To bridge this gap, we propose a
brand-new pre-training framework, lexicon-bottlenecked masked autoencoder
(LexMAE), to learn importance-aware lexicon representations. Essentially, we
present a lexicon-bottlenecked module between a normal language modeling
encoder and a weakened decoder, where a continuous bag-of-words bottleneck is
constructed to learn a lexicon-importance distribution in an unsupervised
fashion. The pre-trained LexMAE is readily transferred to the lexicon-weighting
retrieval via fine-tuning. On the ad-hoc retrieval benchmark, MS-Marco, it
achieves 42.6% MRR@10 with 45.8 QPS for the passage dataset and 44.4% MRR@100
with 134.8 QPS for the document dataset, by a CPU machine. And LexMAE shows
state-of-the-art zero-shot transfer capability on BEIR benchmark with 12
datasets.Comment: Appeared at ICLR 202
Synergistic Interplay between Search and Large Language Models for Information Retrieval
Information retrieval (IR) plays a crucial role in locating relevant
resources from vast amounts of data, and its applications have evolved from
traditional knowledge bases to modern retrieval models (RMs). The emergence of
large language models (LLMs) has further revolutionized the IR field by
enabling users to interact with search systems in natural languages. In this
paper, we explore the advantages and disadvantages of LLMs and RMs,
highlighting their respective strengths in understanding user-issued queries
and retrieving up-to-date information. To leverage the benefits of both
paradigms while circumventing their limitations, we propose InteR, a novel
framework that facilitates information refinement through synergy between RMs
and LLMs. InteR allows RMs to expand knowledge in queries using LLM-generated
knowledge collections and enables LLMs to enhance prompt formulation using
retrieved documents. This iterative refinement process augments the inputs of
RMs and LLMs, leading to more accurate retrieval. Experiments on large-scale
retrieval benchmarks involving web search and low-resource retrieval tasks
demonstrate that InteR achieves overall superior zero-shot retrieval
performance compared to state-of-the-art methods, even those using relevance
judgment. Source code is available at https://github.com/Cyril-JZ/InteRComment: Pre-print. Work in progres
A New Unified Solution for Deep Tunnels in Water-Rich Areas considering Pore Water Pressure
Pore water pressure has an important influence on the stresses and deformation of the surrounding rock of deep tunnels in water-rich areas. In this study, a mechanical model for deep tunnels subjected to a nonuniform stress field in water-rich areas is developed. Considering the pore water pressure, a new unified solution for the stresses, postpeak zone radii, and surface displacement is derived based on a strain-softening model and the Mogi-Coulomb criterion. Through a case study, the effects of pore water pressure, intermediate principal stress, and residual cohesion on the stress distribution, postpeak zone radii, and surface displacement are also discussed. Results show that the tangential stresses are always larger than the radial stress. The radial stress presents a gradually increasing trend, while the tangential stress presents a trend of first increasing and then decreasing, and the maximum tangential stress appears at the interface between the elastic and plastic zones. As the pore water pressure increases, the postpeak zone radii and surface displacement increase. Because of the neglect of the intermediate principal stress in the Mohr-Coulomb criterion, the postpeak zone radii, surface displacement, and maximum tangential stress solved by the Mohr-Coulomb criterion are all larger than those solved by the Mogi-Coulomb criterion. Tunnels surrounded by rock masses with a higher residual cohesion experience lower postpeak zone radii and surface displacement. Data presented in this study provide an important theoretical basis for supporting the tunnels in water-rich areas
The Influence of Tip Clearance on the Performance of a High-Speed Inducer Centrifugal Pump under Different Flow Rates Conditions
The influence mechanism of the blade tip clearance (TC) of an inducer on the performance of a centrifugal pump at high speed was researched under different flow rate conditions in this work. An experiment on the pump’s external performance was carried out, and numerical calculation was also performed under four different TCs. The full characteristic performance curves, static pressure and pressure pulsation distributions of the pump were obtained. Through the research and analysis, it was found that the influence of the TC on the efficiency and the head of the centrifugal pump are related to the flow rate. Under the influence of a large flow rate, the increase in the TC is helpful to improve the efficiency and the head of the pump. The increase in the TC helps to weaken the gap jet effect on the inducer. The inlet jet of the inducer, caused by TC leakage, will form a low-pressure vortex zone at the inlet of the inducer. The splitter-bladed inducer’s pressure pulsation is affected by the TC. The peak pressure pulsation at the monitoring point at the short blades is larger than that at the long blades. With the increase in TC, the cavitation degree at the inlet of the long blade of the inducer is decreased, while the cavitation degree at the short blade is deepened. It is also found that the TC has little effect on the radial force of the inducer and the impeller. These results will provide the design basis for the tip clearance of an inducer
How Safety Climate Impacts Safety Voice—Investigating the Mediating Role of Psychological Safety from a Social Cognitive Perspective
Safety voice has become a popular research topic in the organizational safety field because it helps to prevent accidents. A good safety climate and psychological safety can motivate employees to actively express their ideas about safety, but the specific mechanisms of safety climate and psychological safety, on safety voice, are not yet clear. Based on the “environment-subject cognition-behavior” triadic interaction model of social cognitive theory, this paper explores the relationship between safety climate and safety voice, and the mediating role of psychological safety. We collected questionnaires and conducted data analysis of the valid questionnaires using analytical methods such as hierarchical regression, stepwise regression, and the bootstrap sampling method. We found that safety climate significantly and positively influenced safety voice, and psychological safety played a mediating role between safety climate and safety voice, which strengthened the positive relationship between them. From the research results, it was clear that to stimulate employees to express safety voice behavior, organizations should strive to create a good safety climate and pay attention to building employees’ psychological safety. The findings of this paper provide useful insights for the management of employee safety voice behavior in enterprises
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