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자연어를 활용한 SQL문 생성을 위한 합성곱 신경망 기반 칼럼 예측 모델
정윤기,김동민,이종욱 한국정보과학회 2019 정보과학회논문지 Vol.46 No.2
To retrieve massive data using relational database management system (RDBMS), it is important to understanding of table schemas and SQL grammar. To address this issue, many studies have recently been carried out to generate an SQL query from a natural language question. However, the existing works suffer mostly from predicting columns at where clause and the accuracy is greatly reduced when there are multiple columns to be predicted. In this paper, we propose a convolutional neural network model with column attention mechanism that effectively extracts the latent representation of input question which helps column prediction of the model. The experiment shows that our model outperforms the accuracy of the existing model (SQLNet) by 6%. 관계형 데이터베이스 시스템을 이용하여 대규모의 데이터를 검색하기 위해서는 테이블 스키마 및 SQL문을 이해해야 하는 필요성이 있다. 이를 해결하기 위해 자연어가 입력으로 주어질 때, 이에 대응하는 SQL문을 생성하는 연구가 최근 진행되고 있다. 기존 연구에서 가장 어려운 부분은 SQL문의 조건에 해당되는 칼럼을 효과적으로 예측하는 부분이며, 예측해야 하는 칼럼의 개수가 여러 개일 때 정확도가 크게 떨어지는 문제점이 있다. 본 논문에서는 칼럼 어텐션 메카니즘을 이용하여, 자연어 데이터의 숨겨진 표현을 효과적으로 추출하는 합성곱 신경망 모델을 제안한다. 본 연구의 제안 방법은 기존 방법 대비 약 6% 이상 정확도가 향상되는 것을 확인할 수 있었다.
Enzyme-catalyzed catechol conjugated chitosan for wet tissue adhesives
정윤기,박미경 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1
Tissue adhesive materials still have limitations to achieve strong adhesion to wet tissue as well as superior mechanical properties. In this study, catechol conjugated chitosan matrices were fabricated via enzymatic synthesis for tissue adhesives. The adhesive and cohesive forces were optimized by controlling the degree of cross-linking affected by oxidation degree of the catechol. The physico-chemical characteristics, mechanical properties, and bio-compatibility were also studied to evaluate the performances of catechol-conjugated chitosan matrices. Our results suggest that matrices of chitosan derivatives underbalanced cohesion and adhesion would be promising materials applicable for surgical adhesives and hemostat.
정윤기,김윤아,( Md Lemon Hasan ),( So Young Chun ),( Seung Kwon You ),( Tae Gyun Kwon ),한동근,( Won-gun Koh ) 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
In recent year, renal tissue regeneration with the help of extracellular matrix (ECM) derived scaffold is expected to be a promising strategy. Extracellular matrix (ECM) derived scaffold owing to its highly biocompatiblity and ability to guid renel tissue regeneration. In our previous study, magnesium hydroxide nanoparticles incorporated three dimensional porous PLGA scaffold was directly coated with fibroblast derived extracellular matrix. Inspired from previous study, here we have prepared nephron progenitor cell containing ECM surface- modified scaffolds for renal tissue regeneration. In in vitro cell studies with NPCs, modified scaffold showed improved cell viability and significantly increased growth factor release in respective time. An 8-week post implantation study conducted on kidney model demonstrated that modified scaffold reduced the expression of fibrogenesis inducing cytokine marker and accelerated the renal tissue regeneration with a low inflammatory response.