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      <title-group>
        <article-title>NCU-IISR: Enhancing Biomedical Question Answering with GPT-4 and Retrieval Augmented Generation in BioASQ 12b Phase B</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Bing-Chen Chih</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jen-Chieh Han</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Richard Tzong-Han Tsai</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Computer Science and Information Engineering, National Central University</institution>
          ,
          <country country="TW">Taiwan</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Research Center for Humanities and Social Sciences</institution>
          ,
          <addr-line>Academia Sinica</addr-line>
          ,
          <country country="TW">Taiwan</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>In this paper, we introduce our system and submissions in BioASQ 12b phase b [1], highlighting a significant improvement with GPT-4 and the integration of Retrieval Augmented Generation (RAG) techniques. We describe our prompt engineering methods and the experimental procedures followed. Because GPT-4 has proven efectiveness in generating answers and its ability in the biological domain, our system utilizes GPT-4 to address biomedical question-answering (QA). Leveraging OpenAI's ChatCompletions API, we refined previous prompt engineering approaches [2] for BioASQ 11b phase b. This year, the addition of RAG techniques significantly improved the information retrieval capabilities of our system. Consequently, our latest submission employed what we experimented to be the most efective prompts and techniques, achieving excellent performance across multiple metrics in the fourth batch.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Biomedical Question Answer</kwd>
        <kwd>Large Language Models (LLMs)</kwd>
        <kwd>Generative Pre-trained Transformer</kwd>
        <kwd>Retrieval Augmented Generation</kwd>
      </kwd-group>
    </article-meta>
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    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        BioASQ [3] has been at the forefront of advancing biomedical semantic indexing and question-answering
through its annual challenges since 2013. The 12th time of BioASQ, specifically Task 12b Phase B[
        <xref ref-type="bibr" rid="ref1">1</xref>
        ],
tasks participants with generating exact or ideal answers to biomedical questions using provided text
snippets. This year’s training dataset comprises 5,046 questions, which includes the previous year’s test
set annotations with gold answers, along with 340 new test questions for evaluation. These questions are
organized into four batches, each containing 85 questions, meticulously crafted by a team of biomedical
experts. The questions in Task 12b Phase B are categorized into four types: yes/no, factoid, list, and
summary. Among these, the yes/no, factoid, and list questions require exact answers, while all types
require an ideal answer. Participants can submit up to five results per batch, encouraging continuous
optimization of their models and techniques. By structuring these rigorous challenges, BioASQ aims
to drive innovation and enhance the capabilities of information retrieval systems in the biomedical
domain.
      </p>
      <p>Table 1 illustrates examples across four categories in the BioASQ dataset. Each instance contains a
question along with several snippets, and answers are categorized into "ideal answer" and "exact answer."
Notably, in the "summary" category, there is no requirement for an "exact answer." Last year, we leveraged
the understanding capabilities of GPT-4 combined with prompt engineering techniques, achieving
great results. This year, we continue to utilize GPT-4’s comprehension abilities while incorporating
Retrieval-Augmented Generation (RAG) techniques. By harnessing RAG’s retrieval capabilities, we
enhance the model’s domain knowledge, thereby improving output performance. Additionally, we
conducted a deeper analysis of the dataset and refined the answer generation approach. Furthermore,
we continued to implement prompt engineering techniques, ensuring a robust and efective approach
to improving model responses.</p>
      <p>Yes/No
Question
Exact Answer
Ideal Answer
List
Question
Exact Answer
Ideal Answer
Factoid
Question
Exact Answer
Ideal Answer
Summary
Question
Ideal Answer</p>
      <p>Can modulation of KCNQ1 splicing prevent arrhythmias?
yes
Amiloride reduces arrhythmogenicity through the modulation of
KCNQ1 splicing. Therefore, the modulation of KCNQ1 splicing may
help prevent arrhythmias.</p>
      <p>Which drugs are included in the AZD7442?
[tixagevimab, cilgavimab]
AZD7442 is a combination of two long-acting monoclonal antibodies
tixagevimab and cilgavimab. It has been authorized for the prevention
and treatment of coronavirus disease 2019 (COVID-19).</p>
      <p>Olokizumab is tested for which disease?
[rheumatoid arthritis]
Olokizumab, a monoclonal antibody against interleukin 6, improves
outcomes of rheumatoid arthritis.</p>
      <p>What is the definition of dermatillomania?
Dermatillomania is a condition that leads to repetitive picking of their
skin ending up in skin and soft tissue damage. It is a chronic,
recurrent, and treatment resistant neuropsychiatric disorder with an
underestimated prevalence that has a concerning negative impact on
an individual’s health and quality of life.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Related Work</title>
      <p>The biomedical domain is characterized by extensive specialized knowledge and complex terminology,
making the process of acquiring and applying this information both intricate and time-consuming.
Traditional methods often involve reading a substantial number of academic papers, which requires not
only significant professional expertise but also considerable efort and time. This approach is ineficient,
failing to quickly meet the needs of both professionals and the general public.</p>
      <p>Natural Language Processing (NLP) based Question-Answering (QA) systems provide a promising
solution to these challenges. By leveraging advanced language models, these systems can interpret,
retrieve, and generate responses from medical texts, significantly enhancing the eficiency of QA tasks.
Consequently, QA systems streamline the process of accessing biomedical information, making it faster
and more eficient for both experts and the general public. With the continuous advancements in deep
learning technologies, QA models based on these techniques are progressively bridging the gap between
complex biomedical data and practical usability, facilitating broader knowledge dissemination and
application.</p>
      <p>Prompt Engineering Prompt engineering has emerged as a critical technique in the field of natural
language processing (NLP) and machine learning, particularly in the utilization of large language models
like GPT-3 and GPT-4 [4]. This technique involves crafting specific prompts or input queries that guide
the language model to produce desired outputs. Various studies have highlighted the efectiveness
of prompt engineering in improving the performance of language models across diferent tasks. For
instance, Brown et al. [5] demonstrated that by carefully designing prompts, the accuracy of few-shot
learning in GPT-3 significantly increased, enabling the model to perform complex tasks with minimal
examples. This approach has been widely adopted in various applications, including question-answering,
text summarization, and language translation.</p>
      <p>Retrieval Augmented Generation Retrieval Augmented Generation (RAG) is a technique that
combines retrieval-based methods with generative models to enhance the relevance and accuracy of
generated text. Initially introduced by Lewis et al. [6], RAG has demonstrated significant improvements
in open-domain question answering by retrieving relevant documents and using them to inform the
generation process.</p>
      <p>In the RAG framework, the process typically involves two main components: the retriever and the
generator. The retriever is responsible for fetching relevant documents or snippets from a large corpus
based on the input query. This is usually achieved using a dense passage retrieval (DPR) model, which
encodes both the query and the documents into dense vectors and retrieves the most similar documents.
The generator then takes these retrieved documents, concatenates them with the query, and generates
a response using a generative model such as GPT-4. This combination allows the generative model to
produce more accurate and contextually relevant answers by leveraging the additional context provided
by the retrieved documents.</p>
      <p>In the biomedical domain, RAG has been particularly beneficial due to the complexity and specificity
of the information. Systems utilizing RAG can retrieve pertinent biomedical literature, thus improving
the contextual relevance and accuracy of the generated answers. This approach has shown promising
results in challenges such as BioASQ.</p>
      <p>Our work leverages RAG to enhance our GPT-4-based system for the BioASQ 12b phase B challenge.
By integrating RAG, we aim to improve the retrieval and utilization of relevant biomedical documents,
ensuring that generated answers are well-supported by accurate and relevant information. This
integration enhances the generative capabilities of GPT-4, providing more reliable answers in the biomedical
context.</p>
    </sec>
    <sec id="sec-3">
      <title>3. Method</title>
      <sec id="sec-3-1">
        <title>3.1. Dataset</title>
        <p>The BioASQ Task 12b Phase B dataset [7] provided 5,049 training data samples, comprising 1,210
summary type samples, 1,515 factoid type samples, 967 list type samples, and 1,357 yes/no type samples.
Each sample included multiple snippets along with their source documents. Last year, due to the token
limit of OpenAI’s API, we summarized the snippets and selected the top five snippets. This year, we
resolved this practice and found that the performance did not drop, while allowing us to access more
comprehensive information.</p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. Prompting</title>
        <p>Snippets: For each question, we incorporate all available snippets as references. Although last year
we observed that the top five snippets could cover most of the necessary information, we found that
considering all snippets results in more accurate model outputs. Therefore, we provide the model with
all snippets listed before the question and prompt for reference. To use Retrieval-Augmented Generation
(RAG), we compile all snippets into a database for the model to retrieve relevant information efectively.</p>
        <p>Questions: When directly using GPT-4 to generate both the ideal answer and the exact answer
simultaneously, we retained most of the prompts from last year. We instructed the model to generate
responses in JSON format and to keep the replies as concise as possible. In cases where the ideal answer
and exact answer are generated separately, we first focused on generating a high-quality ideal answer.
This is based on our observation that the entities in the exact answer typically appear in the ideal
answer. Therefore, the model is first tasked with generating a well-crafted ideal answer, and then it
generates the exact answer based on this ideal answer. In both stages, snippets are provided, and during
the exact answer generation, few-shot examples are included to ensure accuracy.Please refer to Table
2 for the details of the relevant prompts for generating answer separately, and the other prompts are
mostly the same with the prompts we used last year.</p>
        <p>In Batch-4, we observed that the ideal answers from previous tests often contained complete segments
from the snippets. Therefore, in this batch, we instructed the model to duplicate snippet fragments into
the ideal answer during generation. This approach resulted in significantly improved outcomes.</p>
      </sec>
      <sec id="sec-3-3">
        <title>3.3. Strategy</title>
        <p>Prompts
Reply to the answer clearly and easily in less than 3 sentences. You should read the
chat history’s content before answer the question. You can directly copy part of the
above snippets as part of your answer. The question is: {QUESTION_BODY}
Please answer me only yes or no. You should read the ideal_answer and snippets before
answer the question.</p>
        <p>Please answer me and follow the following rules: 1. Give me a list of precise key
entities to answer the question, as clear and concise as possible. 2. You should read the
ideal_answer and snippets before answer the question.</p>
        <p>Please answer me and follow the following rules: 1. Give me a list of precise key entities
to answer the question, as clear and concise as possible. 2. The list should contain at
least 1 and up to 5 entity names, ordered by decreasing confidence. 3. You should read
the ideal_answer and snippets before answer the question.</p>
        <p>Our approach primarily consists of two strategies for generating answers: direct generation of both
ideal and exact answers, and sequential generation of these answers. This idea draws from the
chain-ofthought methodology [? ]. In cases where we observed that generating exact answers directly often
resulted in responses that were either imprecise or overly verbose, we provided few-shot examples to
refine the accuracy of the answers. However, our experiments showed that separate generation does
not consistently outperform direct generation; in most scenarios, direct generation proved suficiently
efective.</p>
        <p>To enhance the model’s understanding of the provided snippets or documents, we adopted the
Retrieval-Augmented Generation (RAG) [6] technique. In our implementation, we used the OpenAI
"text-embedding-ada-002" embedding model for embedding both the query and the snippets, which
provided high-quality dense representations and improved retrieval accuracy. The retrieval process
involved encoding the input query and the snippets using the OpenAI embedding model, retrieving the
top-k(k = 4) most relevant snippets via computing cosine similarity between the query and documents,
and then directly concatenating these snippets with the query to form the prompt for GPT-4.</p>
        <p>Although there is a risk of retrieving incorrect fragments, our experiments indicate that this risk has
minimal impact on the task’s overall performance. In our detailed analysis of the dataset, we observed
that standard ideal answers from previous years often contained segments identical to those in the
snippets. As a result, in Batch-4, we modified our prompts to allow the model to appropriately duplicate
snippet fragments into the answers. This adjustment led to improvements in automated evaluations.</p>
        <p>Furthermore, we experimented with adjusting the model’s temperature settings. We found that
setting the temperature to 0 often produced the highest quality outputs, although this setting was
not consistently stable and sometimes resulted in suboptimal performance in certain cases.Overall,
our integration of RAG significantly enhanced the performance of our system by providing more
contextually relevant and accurate information, thus improving the quality of the generated answers in
the BioASQ 12b challenge.</p>
      </sec>
      <sec id="sec-3-4">
        <title>3.4. Systems</title>
        <p>We use diferent systems in diferent batches. The detailed configuration of each system can be seen in
Table 3. Please note that Batch-1 has no recorded configuration due to some errors.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Result</title>
      <p>Our results are presented separately for Exact Answer (Table 4) and Ideal Answer (Table 5). We observed
significant improvements in Batch-4, where prompt modifications and strategy adjustments were
implemented. These changes led to noticeable performance improvement. Although the Manual Score
has not yet been released, we achieved competitive rankings across various metrics in the automated
evaluations. Our experiments demonstrated that employing Retrieval-Augmented Generation (RAG) to
enhance domain knowledge comprehension significantly benefited our Question Answering system,
proving to be a crucial component worth considering.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Discussion and Conclusions</title>
      <p>In this task, we conducted extensive testing on various techniques. Initially, we considered that
focusing the model on generating only one type of answer might yield better performance. However,
our experiments revealed that the model’s ability to simultaneously generate both ideal and exact
answers was equally efective. By utilizing the Retrieval-Augmented Generation (RAG) technique,
we calculated the similarity between queries and medical texts, extracting text directly relevant to
the questions. This allowed the model to focus on high-quality data when formulating answers. Our
experiments confirmed that this approach improved the model’s performance. Future work could explore
strategies for segmenting snippet documents, which may further enhance efectiveness. Additionally,
continuous refinement of prompt engineering and RAG integration could lead to even more significant
improvements in answer accuracy and relevance.
[2] Y.-W. L. J.-C. H. W. M. R. T.-H. T. Chun-Yu Hsueh, Yu Zhang, Ncu-iisr: Prompt engineering on gpt-4
to stove biological problems in bioasq 11b phase b, CEUR Workshop Proceedings 3497 (2023).
[3] A. Nentidis, G. Katsimpras, A. Krithara, S. Lima-López, E. Farré-Maduell, M. Krallinger,
N. Loukachevitch, V. Davydova, E. Tutubalina, G. Paliouras, Overview of BioASQ 2024: The
twelfth BioASQ challenge on Large-Scale Biomedical Semantic Indexing and Question Answering,
in: L. Goeuriot, P. Mulhem, G. Quénot, D. Schwab, L. Soulier, G. Maria Di Nunzio, P. Galuščáková,
A. García Seco de Herrera, G. Faggioli, N. Ferro (Eds.), Experimental IR Meets Multilinguality,
Multimodality, and Interaction. Proceedings of the Fifteenth International Conference of the CLEF
Association (CLEF 2024), 2024.
[4] OpenAI, Gpt-4 technical report, 2023. arXiv:2303.08774.
[5] T. B. Brown, B. Mann, N. Ryder, M. Subbiah, J. D. Kaplan, P. Dhariwal, A. Neelakantan, P. Shyam,
G. Sastry, A. Askell, et al., Language models are few-shot learners, arXiv preprint arXiv:2005.14165
(2020).
[6] P. Lewis, E. Perez, A. Piktus, F. Petroni, V. Karpukhin, N. Goyal, H. Küttler, M. Lewis, W.-t. Yih,
T. Rocktäschel, S. Riedel, D. Kiela, Retrieval-augmented generation for knowledge-intensive nlp
tasks, in: Advances in Neural Information Processing Systems, volume 33, 2020, pp. 9459–9474.
URL: https://proceedings.neurips.cc/paper/2020/hash/6b493230205f780e1bc26945df7481e5-Abstract.
html.
[7] A. Krithara, A. Nentidis, K. Bougiatiotis, G. Paliouras, BioASQ-QA: A manually curated corpus for
Biomedical Question Answering, Scientific Data 10 (2023) 170.</p>
    </sec>
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  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>A.</given-names>
            <surname>Nentidis</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G.</given-names>
            <surname>Katsimpras</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Krithara</surname>
          </string-name>
          ,
          <string-name>
            <surname>G.</surname>
          </string-name>
          <article-title>Paliouras, Overview of BioASQ Tasks 12b and Synergy12 in CLEF2024</article-title>
          , in: G. Faggioli,
          <string-name>
            <given-names>N.</given-names>
            <surname>Ferro</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Galuščáková</surname>
          </string-name>
          ,
          <string-name>
            <surname>A</surname>
          </string-name>
          . García Seco de Herrera (Eds.),
          <source>Working Notes of CLEF 2024 - Conference and Labs of the Evaluation Forum</source>
          ,
          <year>2024</year>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
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