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A Research on Accuracy Improvement of Diabetes Recognition Factors Based on XGBoost
Yongsub Shin,Dai Yeol Yun,Seok-Jae Moon,Chi-gon Hwang 한국인터넷방송통신학회 2021 Journal of Advanced Smart Convergence Vol.10 No.2
Recently, the number of people who visit the hospital due to diabetes is increasing. According to the Korean Diabetes Association, it is statistically indicated that one in seven adults aged 30 years or older in Korea suffers from diabetes, and it is expected to be more if the pre-diabetes, fasting blood sugar disorders, are combined. In the last study, the validity of Triglyceride and Cholesterol associated with diabetes was confirmed and analyzed using Random Forest. Random Forest has a disadvantage that as the amount of data increases, it uses more memory and slows down the speed. Therefore, in this paper, we compared and analyzed Random Forest and XGBoost, focusing on improvement of learning speed and prevention of memory waste, which are mainly dealt with in machine learning. Using XGBoost, the problem of slowing down and wasting memory was solved, and the accuracy of the diabetes recognition factor was further increased.
SlashBurn: Graph Compression and Mining beyond Caveman Communities
Yongsub Lim,Kang, U.,Faloutsos, Christos IEEE 2014 IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERIN Vol.26 No.12
<P>Given a real world graph, how should we lay-out its edges? How can we compress it? These questions are closely related, and the typical approach so far is to find clique-like communities, like the cavemen graph', and compress them. We show that the block-diagonal mental image of the cavemen graph' is the wrong paradigm, in full agreement with earlier results that real world graphs have no good cuts. Instead, we propose to envision graphs as a collection of hubs connecting spokes, with super-hubs connecting the hubs, and so on, recursively. Based on the idea, we propose the SLASHBURN method to recursively split a graph into hubs and spokes connected only by the hubs. We also propose techniques to select the hubs and give an ordering to the spokes, in addition to the basic SLASHBURN. We give theoretical analysis of the proposed hub selection methods. Our view point has several advantages: (a) it avoids the no good cuts' problem, (b) it gives better compression, and (c) it leads to faster execution times for matrix-vector operations, which are the back-bone of most graph processing tools. Through experiments, we show that SLASHBURN consistently outperforms other methods for all data sets, resulting in better compression and faster running time. Moreover, we show that SLASHBURN with the appropriate spokes ordering can further improve compression while hardly sacrificing the running time.</P>
Yttria stabilized zirconia films deposited by electro-spray deposition for solid oxide fuel cells
Yongsub Yoon,임종모,신동욱 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.2
Solid oxide fuel cells(SOFCs) are interesting as an energy conversion system of the future with high efficiency and environmental cleanness. To fabricate the micro-fuel cell for mobile applications, it is essential to develop a process for the deposition of dense electrolyte films. In this study, for a micro-SOFC application, YSZ electrolyte films were prepared by an electro-spray deposition (ESD) method. The deposition parameters studied were deposition temperature, distance between nozzle and substrate, solution concentration and DC voltage. Depending on these parameters, the surfaces were remarkably changed from cracked or rough surfaces to smooth and dense films. Dense films was prepared with the conditions of a nozzlesubstrate distance of 4 cm, a deposition temperature of 150℃, a deposition time of 4 minutes, and a voltage of 16 kV. Solid oxide fuel cells(SOFCs) are interesting as an energy conversion system of the future with high efficiency and environmental cleanness. To fabricate the micro-fuel cell for mobile applications, it is essential to develop a process for the deposition of dense electrolyte films. In this study, for a micro-SOFC application, YSZ electrolyte films were prepared by an electro-spray deposition (ESD) method. The deposition parameters studied were deposition temperature, distance between nozzle and substrate, solution concentration and DC voltage. Depending on these parameters, the surfaces were remarkably changed from cracked or rough surfaces to smooth and dense films. Dense films was prepared with the conditions of a nozzlesubstrate distance of 4 cm, a deposition temperature of 150℃, a deposition time of 4 minutes, and a voltage of 16 kV.
Antimicrobial Activity and Toxicity of Preservative Chemicals
Yongsub Yi 호서대학교 기초과학연구소 2016 기초과학연구 논문집 Vol.24 No.1
Parabens are alkyl esters of p-hydroxy benzoic acid which are widely used in foods, cosmetics, and pharmacological products as preservatives. Actually, human body is exposed to various parabens in the above products. This study was conducted to determine the toxicity of paraben by various concentration of butyl paraben, methyl paraben, propyl paraben, and 1,2 hexane diol in the three field of microorganisms, human keratinocyte, and zebra fish. The highest rate of growth inhibition was shown in microbial study of buthyl paraben. 1,2 hexane diol had the lowest cytotoxic effect and Methyl paraben had the highest in human keratinocyte. We have monitored the growth pattern of zebrafish at the time point (1,2,3, and 4 day). The toxicity induced the embryo mortality, morphological malformation, and disturbance in heart-beating. Methyl paraben was significantly increased the mortality rate in zebrafish embryo. In assessing the morphological malformations, most parabens did show the adverse effect, but 1,2 hexane diol did not shown.