• 대한예방의학회:학술대회논문집
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• 대한예방의학회 2004년도 제56차 추계 학술대회 연제집
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• pp.48.2-49
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• 2004

• 수면정신생리
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• 제4권2호
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• pp.140-146
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• 1997

Sleep-related breathing disorders, especially sleep apnea syndrome are complicated by neuropsychiatric dysfunction such as excessive daytime sleepiness, cognitive dysfunction, and depression. As the determinants of daytime sleepiness, sleep fragmentation is more influential than nocturnal hypoxia. Daytime sleepiness can be improved by continuous positive airway pressure (CPAP) or surgery in up to 95% of the treated subjects. Both sleepiness and nocturnal hypoxia would cause cognitive dysfunction. While impairments in attention and verbal memory are more related with sleepiness and prominent in mild to moderate sleep apnea syndrome (SAS), impairments in general intellectual function and executive function are more related with nocturnal hypoxia and prominent in severe SAS. Several cognitive deficits related with nocturnal hypoxia may be irreversible despite CPAP or surgical treatments. So, early detection and early appropriate treatment of SAS would prevent sleepiness and cognitive deterioration.

• Korean Chemical Engineering Research
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• 제55권2호
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• pp.225-229
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• 2017

최근 약물전달시스템으로 널리 주목받고 있는 dextran의 미립자는 초임계 반용매 공정을 통해 얻을 수 있다. 초임계 반용매(SAS) 공정에서는 DMSO (dimethyl sulfoxide)에 용해되어 있는 dextran이 반용매인 초임계 $CO_2$의 첨가에 의한 재결정으로 얻어진다. 본 연구에서는 이 공정의 적절한 운전조건을 제시하기 위하여 가변부피 셀을 이용하여 cloud point를 측정함으로써 Dexran/DMSO/$CO_2$의 상거동을 관찰하였다 실험결과로부터 dextran 미립자 제조를 위한 초임계 반용매 공정의 적절한 온도(300.15 K~330.15 K), 압력(90 bar~130 bar), 용질의 농도(5 mg/ml~20 mg/ml)의 범위를 결정하였다.

• Wind and Structures
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• 제37권4호
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• pp.303-314
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• 2023

In this study, two steady RANS turbulence models (SST k-ω and Realizable k-ε) and four unsteady turbulence models (URANS SST k-ω and Realizable k-ε, SST-SAS, and SST-IDDES) are evaluated with respect to their capacity to predict crosswind characteristics on high-speed trains (HSTs). All of the numerical simulations are compared with the wind tunnel values and LES results to ensure the accuracy of each turbulence model. Specifically, the surface pressure distributions, time-averaged aerodynamic coefficients, flow fields, and computational cost are studied to determine the suitability of different models. Results suggest that the predictions of the pressure distributions and aerodynamic forces obtained from the steady and transient RANS models are almost the same. In particular, both SAS and IDDES exhibits similar predictions with wind tunnel test and LES, therefore, the SAS model is considered an attractive alternative for IDDES or LES in the crosswind study of trains. In addition, if the computational cost needs to be significantly reduced, the RANS SST k-ω model is shown to provide relatively reasonable results for the surface pressures and aerodynamic forces. As a result, the RANS SST k-ω model might be the most appropriate option for the expensive aerodynamic optimizations of trains using machine learning (ML) techniques because it balances solution accuracy and resource consumption.

• Communications for Statistical Applications and Methods
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• 제8권2호
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• pp.507-514
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• 2001

In recent years, the development and the embodiment of information analysis system has been sprightly carried out in several fields of study. In this study, as and extension of these studies, we develop a system for multivariate analysis which might be widely used in social and natural sciences. This multivariate analysis system is developed by using multivariate analysis procedures in SAS/STAT software. Also, the system supply users with he environment of GUI(Graphical User Interface), which is constructed with AF(application frame) and SCL(screen control language) of SAS software, in order to help users to use the system with easy.

• 전기학회논문지
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• 제60권11호
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• pp.2028-2034
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• 2011

Substation Automation System (SAS) based on IEC 61850 is becoming more and more reality in applying power systems. As well, the development of various engineering tools and the convergence with diagnostic systems are underway. To reflect recent advancements in SAS technology, the Korea Electric Power Corporation initiated a 154kV SAS pilot project and a smart power grid business in 2010. In this paper, the authors will summarize the overview and the lessons learned in applying the IEC 61850-based 154kV Main transformer bay IED solutions to these two project.

• Composites Research
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• 제17권6호
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• pp.22-27
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• 2004

본 논문은 비대칭 샌드위치 구조체인 표면안테나 구조의 설계 및 제작 그리고 피로거동의 관한 연구이다. 사용될 재료는 전기적 특성. 유전율 그리고 기계적 특성을 동시에 만족하여야 한다. 안테나의 전기적 특성을 위해 샌드위치 구조 층 사이에 마이크로스트립 안테나를 삽입시켰고, 위성통신을 목적으로 적절한 대역에서 설계하였다. 최종 제작된 표면 안테나 구조물은 $16{\;}{\tiems}{\;}8$개의 배열안테나로 설계시의 목적에 부합하는 특성을 나타내었다. 4점 굽힘실험을 통하여 표면안테나 구조물의 정하중 및 피로거동을 분석하였다. 피로하중은 0.75(1.875 kN) 하중수준을 나타내었다. 파단 시 변위는 굽힘실험 변위량인 5 mm 보다 많은 5.42 mm에서 파괴가 발생함을 볼 수 있었다. 피로실험결과와 단일하중 시의 피로수명 예측 식을 비교하였다.

• Journal of the Korean Data and Information Science Society
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• 제8권2호
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• pp.247-260
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• 1997

The quasi-likelihood models which greatly widened the scope of generalized linear models are widely used in data analysis where a likelihood is not available. Since a quasi-likelihood may not appear to be an ordinary likelihood for any known distribution in the natural exponential family, to fit the quasi-likelihood models the standard statistical packages such as GLIM, GENSTAT, S-PLUS and so on may not directly applied. SAS/IML is very useful for fitting of such models. In this paper, we present simple SAS/IML(version 6.11) program which helps to fit and analyze the quasi-likelihood models applied to the leaf-blotch data introduced by Wedderburn(1974), and the problem with deviance useful generally to model checking is pointed out, and then its solution method is mention through the data analysis based on this quasi-likelihood models checking.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.13-18
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• 2009

Because the existing Human-Machine Interface (HMI) for the conventional substation cannot dynamically indicate the configuration information of the Substation Automation System (SAS). In this paper, an intelligent station HMI is proposed for IEC 61850 based substation. The program of the proposed HMI not only can automatically generate the layout of single line diagram, but can also indicate the communication network and functions of IEDs by reading SCL files. It greatly helps monitor the operation status, communication network and each IED dynamically, such as failure detection in SAS. Furthermore, this paper presents the possibility of developing new software for SAS with the full use of IEC 61850-6. Once the software is complete, there is no need to change it when the substation is upgraded or when it is migrated to other IEC 61850 based substations, which is a cost-effective solution.

• 폴리머
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• 제38권3호
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• pp.293-298
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• 2014

본 연구에서는 방사선을 이용하여 다공성 polytetrafluoroethylene(PTFE) 지지체에 acrylonitrile(AN)과 친수성 작용기를 가진 sodium allylsulfonate(SAS)를 접목시켜 복합 연료전지막의 지지체로 사용되는 친수화 다공성 지지체를 제조하였다. SAS/AN의 몰비율, 단량체 농도, 방사선의 조사선량에 변화를 주어 제조된 지지체의 물성을 평가하였다. 제조된 지지체의 FTIR 분석을 통하여 각 단량체들이 다공성 PTFE 지지체에 성공적으로 그래프팅되었음을 확인하였다. 또한 FE-SEM과 gurley number 측정을 이용하여 그래프트율이 증가할수록 지지체 표면의 기공이 감소하는 것을 관찰하였고, 그래프트율, 접촉각, TBO(toluidine blue O) uptake 분석을 통해 그래프트율이 증가됨에 따라 제조된 지지체의 친수화도가 증가하는 것을 확인하였다.