KaLM-Embedding-V2: Superior Training Techniques and Data Inspire A Versatile Embedding Model

Fuente: arXiv
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Autores principales: Zhao, Xinping, Hu, Xinshuo, Shan, Zifei, Huang, Shouzheng, Zhou, Yao, Zhang, Xin, Sun, Zetian, Liu, Zhenyu, Li, Dongfang, Wei, Xinyuan, Pan, Youcheng, Xiang, Yang, Zhang, Meishan, Wang, Haofen, Yu, Jun, Hu, Baotian, Zhang, Min
Formato: Preprint
Publicado: 2025
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author Zhao, Xinping
Hu, Xinshuo
Shan, Zifei
Huang, Shouzheng
Zhou, Yao
Zhang, Xin
Sun, Zetian
Liu, Zhenyu
Li, Dongfang
Wei, Xinyuan
Pan, Youcheng
Xiang, Yang
Zhang, Meishan
Wang, Haofen
Yu, Jun
Hu, Baotian
Zhang, Min
author_facet Zhao, Xinping
Hu, Xinshuo
Shan, Zifei
Huang, Shouzheng
Zhou, Yao
Zhang, Xin
Sun, Zetian
Liu, Zhenyu
Li, Dongfang
Wei, Xinyuan
Pan, Youcheng
Xiang, Yang
Zhang, Meishan
Wang, Haofen
Yu, Jun
Hu, Baotian
Zhang, Min
contents Recent advancements in Large Language Models (LLMs)-based text embedding models primarily focus on data scaling or synthesis, yet limited exploration of training techniques and data quality, thereby constraining performance. In this work, we propose KaLM-Embedding-V2, a series of versatile and compact embedding models, systematically incentivizing advanced embedding capability in LLMs by superior training techniques and high-quality data. For model architecture, we implement the models on a 0.5B compact size with simple mean-pooling to produce fixed-length embeddings and remove the causal attention mask to enable fully bidirectional representation learning. For training techniques, we propose a progressive multi-stage training pipeline: pre-training on weakly supervised large-scale datasets, fine-tuning with supervised high-quality datasets, and contrastive distillation with fine-grained soft signals, integrated with focal-style reweighting and online hard-negative mixing to emphasize difficult samples and enrich hard negatives, respectively. For training data, we curate over 20 categories for pre-training and 100 categories for fine-tuning and contrastive distillation, to improve both performance and generalization, leveraging task-specific instructions, hard-negative mining, and example-based multi-class labeling to ensure high quality. Combining these techniques, our KaLM-Embedding-V2 series achieves state-of-the-art performance on the Massive Text Embedding Benchmark, outperforming models of comparable size and rivaling models 3-26x larger, setting a new standard for versatile and compact embedding models under 1B parameters.
format Preprint
id arxiv_https___arxiv_org_abs_2506_20923
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle KaLM-Embedding-V2: Superior Training Techniques and Data Inspire A Versatile Embedding Model
Zhao, Xinping
Hu, Xinshuo
Shan, Zifei
Huang, Shouzheng
Zhou, Yao
Zhang, Xin
Sun, Zetian
Liu, Zhenyu
Li, Dongfang
Wei, Xinyuan
Pan, Youcheng
Xiang, Yang
Zhang, Meishan
Wang, Haofen
Yu, Jun
Hu, Baotian
Zhang, Min
Computation and Language
Recent advancements in Large Language Models (LLMs)-based text embedding models primarily focus on data scaling or synthesis, yet limited exploration of training techniques and data quality, thereby constraining performance. In this work, we propose KaLM-Embedding-V2, a series of versatile and compact embedding models, systematically incentivizing advanced embedding capability in LLMs by superior training techniques and high-quality data. For model architecture, we implement the models on a 0.5B compact size with simple mean-pooling to produce fixed-length embeddings and remove the causal attention mask to enable fully bidirectional representation learning. For training techniques, we propose a progressive multi-stage training pipeline: pre-training on weakly supervised large-scale datasets, fine-tuning with supervised high-quality datasets, and contrastive distillation with fine-grained soft signals, integrated with focal-style reweighting and online hard-negative mixing to emphasize difficult samples and enrich hard negatives, respectively. For training data, we curate over 20 categories for pre-training and 100 categories for fine-tuning and contrastive distillation, to improve both performance and generalization, leveraging task-specific instructions, hard-negative mining, and example-based multi-class labeling to ensure high quality. Combining these techniques, our KaLM-Embedding-V2 series achieves state-of-the-art performance on the Massive Text Embedding Benchmark, outperforming models of comparable size and rivaling models 3-26x larger, setting a new standard for versatile and compact embedding models under 1B parameters.
title KaLM-Embedding-V2: Superior Training Techniques and Data Inspire A Versatile Embedding Model
topic Computation and Language
url https://arxiv.org/abs/2506.20923