sentence-transformers safetensors roberta sentence-similarity feature-extraction dataset_size:10K<n<100K loss:MultipleNegativesRankingLoss arxiv:1908.10084 arxiv:1705.00652 base_model:vinai/phobert-base-v2 base_model:finetune:vinai/phobert-base-v2 autotrain_compatible text-embeddings-inference endpoints_compatible region:us