263 research outputs found
Revealing the Blind Spot of Sentence Encoder Evaluation by HEROS
Existing sentence textual similarity benchmark datasets only use a single
number to summarize how similar the sentence encoder's decision is to humans'.
However, it is unclear what kind of sentence pairs a sentence encoder (SE)
would consider similar. Moreover, existing SE benchmarks mainly consider
sentence pairs with low lexical overlap, so it is unclear how the SEs behave
when two sentences have high lexical overlap. We introduce a high-quality SE
diagnostic dataset, HEROS. HEROS is constructed by transforming an original
sentence into a new sentence based on certain rules to form a \textit{minimal
pair}, and the minimal pair has high lexical overlaps. The rules include
replacing a word with a synonym, an antonym, a typo, a random word, and
converting the original sentence into its negation. Different rules yield
different subsets of HEROS. By systematically comparing the performance of over
60 supervised and unsupervised SEs on HEROS, we reveal that most unsupervised
sentence encoders are insensitive to negation. We find the datasets used to
train the SE are the main determinants of what kind of sentence pairs an SE
considers similar. We also show that even if two SEs have similar performance
on STS benchmarks, they can have very different behavior on HEROS. Our result
reveals the blind spot of traditional STS benchmarks when evaluating SEs.Comment: ACL 2023 repl4nlp (representation learning for NLP) workshop poster
paper. Dataset at https://huggingface.co/datasets/dcml0714/Hero
C2KD: Cross-Lingual Cross-Modal Knowledge Distillation for Multilingual Text-Video Retrieval
Multilingual text-video retrieval methods have improved significantly in
recent years, but the performance for other languages lags behind English. We
propose a Cross-Lingual Cross-Modal Knowledge Distillation method to improve
multilingual text-video retrieval. Inspired by the fact that English text-video
retrieval outperforms other languages, we train a student model using input
text in different languages to match the cross-modal predictions from teacher
models using input text in English. We propose a cross entropy based objective
which forces the distribution over the student's text-video similarity scores
to be similar to those of the teacher models. We introduce a new multilingual
video dataset, Multi-YouCook2, by translating the English captions in the
YouCook2 video dataset to 8 other languages. Our method improves multilingual
text-video retrieval performance on Multi-YouCook2 and several other datasets
such as Multi-MSRVTT and VATEX. We also conducted an analysis on the
effectiveness of different multilingual text models as teachers
Natural Language Embedded Programs for Hybrid Language Symbolic Reasoning
How can we perform computations over natural language representations to
solve tasks that require symbolic and numeric reasoning? We propose natural
language embedded programs (NLEP) as a unifying framework for addressing
math/symbolic reasoning, natural language understanding, and instruction
following tasks. Our approach prompts a language model to generate full Python
programs that define functions over data structures which contain natural
language representations of structured knowledge. A Python interpreter then
executes the generated code and prints the output. Despite using a task-general
prompt, we find that this approach can improve upon strong baselines across a
range of different tasks including math and symbolic reasoning, text
classification, question answering, and instruction following. We further find
the generated programs are often interpretable and enable post-hoc verification
of the intermediate reasoning steps
SemStamp: A Semantic Watermark with Paraphrastic Robustness for Text Generation
Existing watermarking algorithms are vulnerable to paraphrase attacks because
of their token-level design. To address this issue, we propose SemStamp, a
robust sentence-level semantic watermarking algorithm based on
locality-sensitive hashing (LSH), which partitions the semantic space of
sentences. The algorithm encodes and LSH-hashes a candidate sentence generated
by an LLM, and conducts sentence-level rejection sampling until the sampled
sentence falls in watermarked partitions in the semantic embedding space. A
margin-based constraint is used to enhance its robustness. To show the
advantages of our algorithm, we propose a "bigram" paraphrase attack using the
paraphrase that has the fewest bigram overlaps with the original sentence. This
attack is shown to be effective against the existing token-level watermarking
method. Experimental results show that our novel semantic watermark algorithm
is not only more robust than the previous state-of-the-art method on both
common and bigram paraphrase attacks, but also is better at preserving the
quality of generation
Ciprofloxacin-resistant Salmonella enterica Typhimurium and Choleraesuis from Pigs to Humans, Taiwan
We evaluated the disk susceptibility data of 671 nontyphoid Salmonella isolates collected from different parts of Taiwan from March 2001 to August 2001 and 1,261 nontyphoid Salmonella isolates from the National Taiwan University Hospital from 1996 to 2001. Overall, ciprofloxacn resistance was found in 2.7% (18/671) of all nontyphoid Salmonella isolates, in 1.4% (5/347) of Salmonella enterica serotype Typhimurium and in 7.5% (8/107) in S. enterica serotype Choleraesuis nationwide. MICs of six newer fluoroquinolones were determined for the following isolates: 37 isolates of ciprofloxacin-resistant (human) S. enterica Typhimurium (N = 26) and Choleraesuis (N = 11), 10 isolates of ciprofloxacin-susceptible (MIC <1 ΞΌg/mL) (human) isolates of these two serotypes, and 15 swine isolates from S. enterica Choleraesuis (N = 13) and Typhmurium (N = 2) with reduced susceptibility to ciprofloxacin (MIC >0.12 ΞΌg/mL). Sequence analysis of the gryA, gyrB, parC, parE, and acrR genes, ciprofloxacin accumulation; and genotypes generated by pulsed-field gel electrophoresis with three restriction enzymes (SpeI, XbaI, and BlnI) were performed. All 26 S. enterica Typhimurium isolates from humans and pigs belonged to genotype I. For S. enterica Choleraesuis isolates, 91% (10/11) of human isolates and 54% (7/13) of swine isolates belonged to genotype B. These two genotypes isolates from humans all exhibited a high-level of resistance to ciprofloxacin (MIC 16β64 ΞΌg/mL). They had two-base substitutions in the gyrA gene at codons 83 (Ser83Phe) and 87 (Asp87Gly or Asp87Asn) and in the parC gene at codon 80 (Ser80Arg, Ser80Ile, or Ser84Lys). Our investigation documented that not only did these two S. enterica isolates have a high prevalence of ciprofloxacin resistance nationwide but also that some closely related ciprofloxacin-resistant strains are disseminated from pigs to humans
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