• Membrane and Water Treatment
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• 제14권2호
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• pp.85-93
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• 2023

Membrane separation is widely used for several applications such as water treatment, membrane reactors and climate change. Cross-linked organic-inorganic hybrid polyvinylidene fluoride (PVDF) / Tetraethyl orthosilicate (TEOS) was adopted for the preparation of optimized hollow membrane (HFM) for membrane distillation or other low pressure separators for mechanical properties and permeability under varying pretreatment schemes. HFMs were prepared on semi-pilot membrane fabrication system. Novel adopted post-treatment schemes involved soaking in glycerol, magnesium sulphate (MgSO₄), sodium hypochlorite (NaOCl), and isopropanol for different durations. All fibers were characterized for morphology using a scanning electron microscope (SEM), surface roughness using atomic force microscope (AFM), elemental composition by examining Energy Dispersive Spectroscopy (EDS), water contact angle (CA°) and porosity. The performance of the fibers was evaluated for pure water permeation flux (PWF). Post-treatment with MgSO₄ gave the highest both tensile modulus and flux. Assessment of properties and performance revealed comparable results with other organic-inorganic separators, HF or flat. In spite of few reported data on post treatment using MgSO₄ in presence of TEOS, this proves the potential of low cost treatment without negative impact on other membrane properties. The flux is also comparable with hypochlorite which manifests substantial precaution requirements in actual industrial use.The relatively high values of flux/bar for sample treated with TEOS, post treated with MgSO₄ and hypochlorite are 88 and 82 LMH/bar respectively.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.101-108
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• 2000

In this study, an expert system was developed to predict the safety of tunnel and choose proper tunnel reinforcement system using fuzzy quantification theory and fuzzy inference rule based on tunnel information database. The expert system developed in this study have two main parts named pre-module and post-module. Pre-module decides tunnel information imput items based on the tunnel face mapping information which can be easily obtained in-situ site. Then, using fuzzy quantification theory II, fuzzy membership function is composed and tunnel safety level is inferred through this membership function. The comparison result between the predicted reinforcement system level and measured ones was very similar. In-situ data were obtained in three tunnel sites including subway tunnel under Han river, This system will be very helpful to make the most of in-situ data and suggest proper applicability of tunnel reinforcement system developing more resonable tunnel support method from dependance of some experienced experts for the absent of guide.

• 소성∙가공
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• 제9권6호
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• pp.567-573
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• 2000

An analysis system for evaluating the design of dieface of stamping press dies is developed. The die design analysis system interfaced with CATIA via universal or NASTRAN data format provides the design information such as binder-wrap, punch contact status, section length change ratio, wrinkle symptom etc., which are crucial in predicting the defects of initial shape of the sheet in the dieface design stage. The graphic post-processor of developed system which displays 3-dimensional shapes of tool and die and analysis results, helps the interpretation of design evaluation. The dieface design analysis system was tested in draw dies of front floor panel and quarter panel of auto-body in order to verify the usefulness and validity of the system The examples show that the developed system would be a good tool in evaluating dieface designs.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.195-201
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• 1996

This paper is mainly forcused on the application of modal analysis In analyze the geometrically non-linear buckling behaviors of large span spatial structures, and the evaluation of each eigen mode affected post-buckling behaviors and buckling loads. Modal analysis is applied . to derivation of the system matrices transforming actual displacement space into generalized coordinates space represented by coefficients multiplied in the linear combination of eigen modes which are independent and orthogonal each other. By using modal analysis method, it will be expected to save the calculating time by computer extremely. For example, we can obtain the satisfactorily good results by using about 7% of total eigen modes only in case of single layer latticed dome. And we can decrease the possibility of divergence on the bifurcation point in the calculation of post-buckling path. Arc-length method and Newton-Raphson iteration method are used to calculate the nonlinear equilibrium path.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.473-478
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• 2003

The purpose of this study is to model the seismic behavior of Welded Unreinforced Flange and Bolted (WUF-B) connections with post-Northridge details and evaluate the system performance of the builidings with WUF-B connections. For this purpose, based on test results, mathematical model of the connections were developed and compared with test results. This connection model take into account both panel zone deformation and connection fractures. Then, SAC Phase II 3 and 9-story buildings were modeled using the connection model developed in this study. From nonlinear static pushover analysis of the buildings, maximum strength, maximum roof drift, and so forth are investigated for the buildings with post-Northridge details. Analysis results were compared with those of buildings with pre-Northridge details and ductile connections with no fractures.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.1139-1146
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• 2009

Collapse of cut slope includes many uncertainties in view of the reason and time. So, in the past, risky cut slopes have been dealt after they've been collapsed through post-management measures. But recently, advanced disaster prevention system is required, and as a part of that RTMS(Real-Time Monitoring System) was developed. In this study, stability of risky cut slope was evaluated by site investigation. To grasp deformation behavior characteristics of slope, numerical analysis based on FEM was performed and using results of that, specific standards for installation of Real-Time Monitoring System were suggested.

• 한국철도학회논문집
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• 제5권3호
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• pp.158-166
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• 2002

In this paper, we introduce the software and hardware of the measurement system for on-line testing and evaluation of high speed railway. The test items focus on the verification of the performance and acquirement of the technical data of the high speed railway system. The software controls the hardware of the measurement system, perform the analysis and calculation of measurement data and acts as interface between users and the system hardware. For this purpose, three programs a measuring program, a monitoring program and post-processing program are developed. The detailed test scenario is in the process of development to closely follow the process of development and design of the system.

• 마케팅과학연구
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• 제6권
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• pp.167-184
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• 2000

Previous models of consumer post-purchase evaluation behavior have treated customer satisfaction as a transaction-specific construct. In the present paper, a conceptual framework that describes customer satisfaction measurement as a process is developed. The framework explains customer satisfaction as a dynamic process encompassing five stages-search, interaction, experience, service, and longevity. It is proposed that organizations should develop information systems to measure customer satisfaction during all five of the stages and disseminate such information throughout the organization as part of their Total Quality Management efforts.

• 한국군사과학기술학회지
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• 제6권1호
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• pp.59-67
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• 2003

Multipath is an inevitable error source in radio navigation system such as GPS, it causes signal tracking errors such as carrier tracking errors, code tracking errors. Since code tracking error is a dominant error in absolute positioning, this paper focuses on the improvement of code tracking performance. This paper proposes a method that detects the change of autocorrelation function's slope and mitigates the multipath error. Also, this paper shows the performance evaluation results by post-processing the digitized RF samples.

• 한국실내디자인학회논문집
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• 제13권5호
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• pp.98-105
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• 2004

The importance of environment has been increased recently, and it has affected architectural area especially no less than any other area. This study performed POE on the housing sectors, which have been approved as ‘The Environment-Friendly Housing Certification (KOEAM 2000)’, to evaluate the recognition and value of the residents. The study employed survey method and the items of questionnaire are based on the detailed criteria of the ‘The Environment-Friendly Housing Certification (KOEAM 2000)’. Through the analysis of investigated substance, this study compared the differences between the quantitative satisfaction and the qualitative satisfaction of the residents, and investigated the differences between the degree of satisfaction and the degree of importance, and the preference to the evaluation criteria. As a result, it is deduced that the qualitative aspects rather than the quantitative aspects affects the satisfaction of residents more in some criteria. It is also investigated that the awareness and requirements level of residents varies according to the demographics, and the differences between the evaluation criteria of the residents and the certification system is also deduced. Through this analysis, this study tried to find the supplemental points of the certification system which pursue the sustainable development and accommodate the requirements of residents.