Chanhee Lee

Mr. Chanhee Lee

Korea University

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 May 2020 in International Journal of Machine Learning and Cybernetics
Verified
Journal Article
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GKGyeongmin Kim
Gyeongmin Kim
CLChanhee Lee
Chanhee Lee
JJJaechoon Jo
Jaechoon Jo
HLHeuiSeok Lim
HeuiSeok Lim

19 March 2020 in Electronics
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JJJaechoon Jo
Jaechoon Jo
SLSeolhwa Lee
Seolhwa Lee
CLChanhee Lee
Chanhee Lee
DLDongyub Lee
Dongyub Lee
HLHeuiSeok Lim
HeuiSeok Lim
The digitization of the fashion industry diversified consumer segments, and consumers now have broader choices with shorter production cycles; digital technology in the fashion industry is attracting the attention of consumers. Therefore, a system that efficiently supports the searching and recommendation of a product is becoming increasingly important. However, the text-based search method has limitations because of the nature of the fashion industry, in which design is a very important factor. Therefore, we developed an intelligent fashion technique based on deep learning for efficient fashion product searches and recommendations consisting of a Sketch-Product fashion retrieval model and vector-based user preference fashion recommendation model. It was found that the “Precision at 5” of the image-based similar product retrieval model was 0.774 and that of the sketch-based similar product retrieval model was 0.445. The vector-based preference fashion recommendation model also showed positive performance. This system is expected to enhance consumers’ satisfaction by supporting users in more effectively searching for fashion products or by recommending fashion products before they begin a search.

24 February 2021 in Applied Sciences
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Journal Article
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CLChanhee Lee
Chanhee Lee
KYKisu Yang
Kisu Yang
TWTaesun Whang
Taesun Whang
CPChanjun Park
Chanjun Park
AMAndrew Matteson
Andrew Matteson
HLHeuiSeok Lim
HeuiSeok Lim
Language model pretraining is an effective method for improving the performance of downstream natural language processing tasks. Even though language modeling is unsupervised and thus collecting data for it is relatively less expensive, it is still a challenging process for languages with limited resources. This results in great technological disparity between high- and low-resource languages for numerous downstream natural language processing tasks. In this paper, we aim to make this technology more accessible by enabling data efficient training of pretrained language models. It is achieved by formulating language modeling of low-resource languages as a domain adaptation task using transformer-based language models pretrained on corpora of high-resource languages. Our novel cross-lingual post-training approach selectively reuses parameters of the language model trained on a high-resource language and post-trains them while learning language-specific parameters in the low-resource language. We also propose implicit translation layers that can learn linguistic differences between languages at a sequence level. To evaluate our method, we post-train a RoBERTa model pretrained in English and conduct a case study for the Korean language. Quantitative results from intrinsic and extrinsic evaluations show that our method outperforms several massively multilingual and monolingual pretrained language models in most settings and improves the data efficiency by a factor of up to 32 compared to monolingual training.

13 January 2021 in Applied Sciences
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Journal Article
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CLChanhee Lee
Chanhee Lee
YKYoung Kim
Young Kim
HJHyesung Ji
Hyesung Ji
YLYeonsoo Lee
Yeonsoo Lee
YHYuna Hur
Yuna Hur
HLHeuiSeok Lim
HeuiSeok Lim
In this paper, we show that parameters of a neural network can have redundancy in their ranks, both theoretically and empirically. When viewed as a function from one space to another, neural networks can exhibit feature correlation and slower training due to this redundancy. Motivated by this, we propose a novel regularization method to reduce the redundancy in the rank of parameters. It is a combination of an objective function that makes the parameter rank-deficient and a dynamic low-rank factorization algorithm that gradually reduces the size of this parameter by fusing linearly dependent vectors together. This regularization-by-pruning approach leads to a neural network with better training dynamics and fewer trainable parameters. We also present experimental results that verify our claims. When applied to a neural network trained to classify images, this method provides statistically significant improvement in accuracy and 7.1 times speedup in terms of number of steps required for training. Furthermore, this approach has the side benefit of reducing the network size, which led to a model with 30.65% fewer trainable parameters.

27 July 2020 in arXiv
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TWTaesun Whang
Taesun Whang
DLDongyub Lee
Dongyub Lee
CLChanhee Lee
Chanhee Lee
KYKisu Yang
Kisu Yang
DODongsuk Oh
Dongsuk Oh
HLHeuiSeok Lim
HeuiSeok Lim
We focus on multi-turn response selection in a retrieval-based dialog system. In this paper, we utilize the powerful pre-trained language model Bi-directional Encoder Representations from Transformer (BERT) for a multi-turn dialog system and propose a highly effective post-training method on domain-specific corpus. Although BERT is easily adopted to various NLP tasks and outperforms previous baselines of each task, it still has limitations if a task corpus is too focused on a certain domain. Post-training on domain-specific corpus (e.g., Ubuntu Corpus) helps the model to train contextualized representations and words that do not appear in general corpus (e.g., English Wikipedia). Experimental results show that our approach achieves new state-of-the-art on two response selection benchmarks (i.e., Ubuntu Corpus V1, Advising Corpus) performance improvement by 5.9% and 6% on R@1.

31 May 2020 in arXiv
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JPJeiyoon Park
Jeiyoon Park
CLChanhee Lee
Chanhee Lee
KKKuekyeng Kim
Kuekyeng Kim
HLHeuiseok Lim
Heuiseok Lim
Despite its notable success in adversarial learning approaches to multi-domain task-oriented dialog system, training the dialog policy via adversarial inverse reinforcement learning often fails to balance the performance of the policy generator and reward estimator. During optimization, the reward estimator often overwhelms the policy generator and produces excessively uninformative gradients. We proposes the Variational Reward estimator Bottleneck (VRB), which is an effective regularization method that aims to constrain unproductive information flows between inputs and the reward estimator. The VRB focuses on capturing discriminative features, by exploiting information bottleneck on mutual information. Empirical results on a multi-domain task-oriented dialog dataset demonstrate that the VRB significantly outperforms previous methods.