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Metadata-Induced Contrastive Learning for Zero-Shot Multi-Label Text Classification

This repository contains the source code for Metadata-Induced Contrastive Learning for Zero-Shot Multi-Label Text Classification.

Links

• Installation
• Quick Start
• Data
• Running
• Citation

Installation

For training, GPUs are strongly recommended. We use one NVIDIA V100 16GB GPU in our experiments.

Dependency

The code is written in Python 3.6. We use PyTorch and HuggingFace transformers to build the model. The dependencies are summarized in the file requirements.txt. You can install them like this:

pip3 install -r requirements.txt

Quick Start

To reproduce the results in our paper, you need to first download the datasets. Two datasets are used in our paper: MAG-CS and PubMed. Once you unzip the downloaded file (i.e., MICoL.zip), you can see three folders: MAG/ is the dataset folder of MAG-CS; PubMed/ is the dataset folder of PubMed; scibert_scivocab_uncased/ is the pre-trained SciBERT model. (The pre-trained SciBERT model is from here.)

Put the three folders under the main directory ./. Then you need to run the following scripts.

Input Preparation

Prepare training and testing data. Training document pairs are generated using document metadata for contrastive learning.

./prepare.sh

Training, Testing, and Evaluation

./run.sh

P@k, NDCG@k, PSP@k, and PSN@k scores (k=1,3,5) will be shown in the last several lines of the output. The prediction results can be found in ./{dataset}_output/prediction_{architecture}.json (e.g., ./MAG_output/prediction_cross.json).

You can change the dataset (MAG or PubMed), the meta-path/meta-graph (10 choices, see the Running section below), and the architecture (bi or cross) in the script.

Data

Two datasets are used in our paper. They were first released in the MATCH project. In this paper, we combine the original training and validation sets together as our unlabeled training set (that being said, we do not know the labels of these documents, and we only utilize their text and metadata information); we use the original testing set as our testing set. Dataset statistics are listed below.

*: Originally, there were 15,809 labels in MAG-CS, but the label "Computer Science" is removed from all papers because it is trivial to predict.

**: Both papers in the "Paper->Paper" edge need to appear in the training set.

The MAG Dataset

After you download the datasets, there are four input files in the MAG/ folder: MAG_train.json, MAG_test.json, MAG_label.json, and MAG_candidates.json.

MAG_train.json has text and metadata information of each training document. Each line is a json record representing one document. For example,

{
  "paper": "2150203549",
  "text": "probabilistic_logic group recommendation via information matching. increasingly web recommender_system face scenarios ...",
  "venue": "WWW",
  "author": [
    "2936723753", "2129454193", "2023330040", "2151628004"
  ],
  "reference": [
    "2051834357", "2164374228", "2172118809"
  ],
  "citation": [
    "2064702560", "2105547690"
  ],
  "label": [
    "119857082", "124101348", "197927960", "49937458", "58489278", "127705205", "109364899", "136764020", "557471498", "2776156558", "21569690"
  ]
}

Here, "paper" is the paper id; "reference" is the list of paper ids the current paper cites; "citation" is the list of paper ids citing the current paper. The "label" field in MAG_train.json is optional. We do not need label information of training documents in our training process.

MAG_test.json has text and label information of each testing document. Each line is a json record representing one document. Its format is identical to a record in MAG_train.json. However, now the "label" field is required for eveluation, and the metadata fields (i.e., "venue", "author", "reference", "citation") become optional. We do not need metadata information of testing documents during inference.

MAG_label.json has the name and description of each label. Each line is a json record representing one label. For example,

{
  "label": "11045955",
  "name": [
    "elgamal encryption"
  ],
  "definition": "in cryptography, the elgamal encryption system is an asymmetric key encryption algorithm ...",
  "combined_text": "elgamal encryption. in cryptography, the elgamal encryption system is an asymmetric key encryption algorithm ..."
}

The "combined_text" field is the concatenation of "name" and "definition".

MAG_candidates.json lists the candidate labels of each testing document (obtained by exact name matching and BM25 retrieval). Each line is a json record representing one testing document. For example,

{
  "paper": "2043341294",
  "label": [
    "60048249", "206134035", "2474386", "165297611", "195324797", "39890363", "70777604", "204321447"
  ],
  "predicted_label": [
    "70777604", "76482347", "192209626", "29808475", "206134035", "2474386", "166553842", "195324797", "165297611", "9628104", "39890363", "5147268", "60048249", "19768560"
  ]
}

Here, "label" is the list of ground-truth label ids of the document (identical to the "label" field in MAG_test.json); "predicted_label" is the list of candidate label ids obtained by exact name matching and BM25 retrieval.

The PubMed Dataset

There are four input files in the PubMed/ folder: PubMed_train.json, PubMed_test.json, PubMed_label.json, and PubMed_candidates.json. Their format is the same as that of their counterpart in the MAG dataset.

Running

The Quick Start section should be enough to reproduce the results in out paper. Here are some more details of running our code.

(1) In prepare.sh, you can choose among different meta-paths/meta-graphs to generate positive training pairs. We support 10 choices of meta-paths/meta-graphs.

(2) In run.sh, you can choose between two different architectures: Bi-Encoder (architecture=bi) and Cross-Encoder (architecture=cross).

Citation

Our implementation is adapted from Poly-Encoder and CorNet. If you find this repository useful, please cite the following paper:

@inproceedings{zhang2022metadata,
  title={Metadata-Induced Contrastive Learning for Zero-Shot Multi-Label Text Classification},
  author={Zhang, Yu and Shen, Zhihong and Wu, Chieh-Han and Xie, Boya and Hao, Junheng and Wang, Ye-Yi and Wang, Kuansan and Han, Jiawei},
  booktitle={WWW'22},
  pages={3162--3173},
  year={2022}
}