250 research outputs found
Unified Detoxifying and Debiasing in Language Generation via Inference-time Adaptive Optimization
Warning: this paper contains model outputs exhibiting offensiveness and
biases. Recently pre-trained language models (PLMs) have prospered in various
natural language generation (NLG) tasks due to their ability to generate fairly
fluent text. Nevertheless, these models are observed to capture and reproduce
harmful contents in training corpora, typically toxic language and social
biases, raising severe moral issues. Prior works on ethical NLG tackle
detoxifying and debiasing separately, which is problematic since we find
debiased models still exhibit toxicity while detoxified ones even exacerbate
biases. To address such a challenge, we propose the first unified framework of
detoxifying and debiasing called UDDIA, which jointly formalizes these two
problems as rectifying the output space. We theoretically interpret our
framework as learning a text distribution mixing weighted attributes. Besides,
UDDIA conducts adaptive optimization of only a few parameters during decoding
based on a parameter-efficient tuning schema without any training data. This
leads to minimal generation quality loss and improved rectification performance
with acceptable computational cost. Experimental results demonstrate that
compared to several strong baselines, UDDIA achieves debiasing and detoxifying
simultaneously and better balances efficiency and effectiveness, taking a
further step towards practical ethical NLG.Comment: Work in Progress. Preprin
Denevil: Towards Deciphering and Navigating the Ethical Values of Large Language Models via Instruction Learning
Large Language Models (LLMs) have made unprecedented breakthroughs, yet their
increasing integration into everyday life might raise societal risks due to
generated unethical content. Despite extensive study on specific issues like
bias, the intrinsic values of LLMs remain largely unexplored from a moral
philosophy perspective. This work delves into ethical values utilizing Moral
Foundation Theory. Moving beyond conventional discriminative evaluations with
poor reliability, we propose DeNEVIL, a novel prompt generation algorithm
tailored to dynamically exploit LLMs' value vulnerabilities and elicit the
violation of ethics in a generative manner, revealing their underlying value
inclinations. On such a basis, we construct MoralPrompt, a high-quality dataset
comprising 2,397 prompts covering 500+ value principles, and then benchmark the
intrinsic values across a spectrum of LLMs. We discovered that most models are
essentially misaligned, necessitating further ethical value alignment. In
response, we develop VILMO, an in-context alignment method that substantially
enhances the value compliance of LLM outputs by learning to generate
appropriate value instructions, outperforming existing competitors. Our methods
are suitable for black-box and open-source models, offering a promising initial
step in studying the ethical values of LLMs
Improved V?shaped interior permanent magnet rotor topology with inward?extended bridges for reduced torque ripple
Interior permanent magnet synchronous machines (IPMSMs) with V-shaped permanent magnet (PM) rotors are widely used as traction motors in electric vehicles because of their high torque density and high efficiency. However, the V-shape IPMSMs have the disadvantages of inevitable torque ripple due to the non-sinusoidal air-gap flux density distribution and the utilisation of the reluctance torque. In this study, with the aim of improving the torque ripple characteristics, a modified V-shaped IPMSM rotor configuration with bridges extended inwards towards the pole centre is proposed to generate a more sinusoidal air-gap flux density waveform. The proposed topology, referred to as ‘Type C’ within this study, is compared with baseline rotor configuration references, namely ‘Type A’ which is a conventional V-shaped PM rotor, as well as ‘Type B’ which is a related configuration with a mechanically non-uniform air gap. The analysis results show that the rotor ‘Type C’ exhibits significant advantages in terms of reducing cogging torque, torque ripple and radial force, without incurring additional air-gap friction losses. Finally, a prototype of the IPMSM with the proposed rotor configuration is manufactured and tested, verifying the predicted benefits experimentally
Delay-dependent exponential stability criteria for stochastic systems with polytopic-type uncertainties
This paper considers the problem of delay-dependent exponential stability in mean square for continuous-time linear stochastic systems with polytopic-type uncertainties and time-varying delay. Based on linear matrix inequalities (LMIs), applying the descriptor model transformation and introducing free weighting matrices, a new type of Lyapunov-Krasovskii functional is constructed and some new delay-dependent and delay-independent exponential stability criteria are respectively obtained. The results include the delay-independent/rate-dependent and delay-dependent/rate-independent exponential stability criteria. The new criteria are less conservative than existing ones. Numerical examples demonstrate the new criteria are effective and are an improvement over existing ones
Angle dependent field-driven reorientation transitions in uniaxial antiferromagnet MnBiTe single crystal
MnBiTe, a two-dimensional magnetic topological insulator with a
uniaxial antiferromagnetic structure, is an ideal platform to realize quantum
anomalous Hall effect. However, the strength of magnetic interactions is not
clear yet. We performed systematic studies on the magnetization and angle
dependent magnetotransport of MnBiTe single crystal. The results show
that the direction of the magnetic field has significant effects on the
critical field values and magnetic structure of this compound, which leads to
different magnetotransport behaviors. The field-driven reorientation
transitions can be utilized to estimate the AFM interlayer exchange interaction
coupling and uniaxial magnetic anisotropy D. The obtained Hamiltonian can well
explain the experimental data by Monte Carlo simulations. Our comprehensive
studies on the field-driven magnetic transitions phenomenon in MnBiTe
provide a general approach for other topological systems with
antiferromagnetism.Comment: 6 figure
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