Speculative Contrastive Decoding

Large language models (LLMs) have shown extraordinary performance in various language tasks, but high computational requirements hinder their widespread deployment. Speculative decoding, which uses amateur models to predict the generation of expert models, has been proposed as a way to accelerate LLM inference. However, speculative decoding focuses on acceleration instead of making the best use of the token distribution from amateur models. We proposed Speculative Contrastive Decoding (SCD), an accelerated decoding method leveraging the natural contrast between expert and amateur models in speculative decoding. Comprehensive evaluations on four benchmarks show that SCD can achieve similar acceleration factors as speculative decoding while further improving the generation quality as the contrastive decoding. The analysis of token probabilities further demonstrates the compatibility between speculative and contrastive decoding. Overall, SCD provides an effective approach to enhance the decoding quality of LLMs while saving computational resources.Comment: Working in Progres

Transversal Propagation Behaviors of Helical Edge States In a QSH System

The transversal propagation of the edge states in a two-dimensional quantum spin Hall system are classified by decay characteristic quantity $\lambda$. Two different modes of the helical edge states exhibit distinct behaviors. The penetration depth is momentum dependent in normal edge states. The finite size gap decays monotonously with sample width, leading to the normal size effect. In contrast, the penetration depth maintains a uniform minimal value in the special edge states with much shorter length. The finite size gap decays non-monotonously with width, leading to the anomalous finite size effect. Real materials are compared in the phase diagram, which explicitly demonstrates their differences. We also propose an intuitive way to search the special edge states in two-dimensional quantum spin Hall system.Comment: 6 pages, 4 figure

SWITCHING THE HORIZONTAL GRF TO THE PATH OF PROGRESSION IN THE TABLE TENNIS FOREHAND DRIVE

Knowing the kinetic strategies of the lower limbs is a crucial factor to investigate the forehand drive which comprises the changes of the foot placement. It is difficult to directly evaluate the movement of feet with the data of ground reaction force (GRF) and impulse (GRI).This study tried to analyze table tennis forehand drives via the GRF and GRI data based upon the anatomical perspective. The motion and the GRF data were collected from eight right-handed Taiwanese elite table tennis players. The horizontal GRF data were transformed to a reference frame and then integrated with time to get the GRI. During the forehand drive shot, the participants performed a greater lateral impulse to cause the trunk rotation and decelerated their body from initial to mid-phase and then accelerated the body to perform a forehand drive shot