• Journal of the Korea Institute of Building Construction
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• v.20 no.3
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• pp.245-252
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• 2020

Synthetic resin formwork is made of lightweight high-density polyethylene(HDPE). This study used a process flow chart that satisfies the system boundary (such as Cradle-to- Product shipmen ) required by ISO FDIS 13352 to evaluate the entire process of synthetic resin foam using. The entire life cycle inventory (LCI) database calculated from input energy sources, materials used, transportation methods, and manufacturing processes at the system boundary was analyzed. Based on the environmental impact assessment index methodology of the Ministry of Environment from the LCI data analysis of synthetic resin formwork, the environmental impact assessment was carried out through classification, normalization, characterization, and weighting process. The experimental results are as follows the amount of CO₂ (carbon) emission considering the number of conversions was about 32% lower than that of the Euroform. This shows that the use of synthetic resin formwork reduces material production by half compared to Euroform and reduces CO₂ (carbon) emissions.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.2
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• pp.141-146
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• 2016

By occasion of propagation of 3D TV, technology of glassless 3D display is increasingly important. Currently, there was no lead technology In this technology. Thus it is important to develop differentiated technology for secure competitiveness. In this paper, We analyze patents for R&D strategy about glassless 3D display. Through Company-Technology matrix analysis and Patent trend analysis, We extract promising technology field and core technology. Lastly We suggest R&D strategy by using patent road map.

• Journal of Korean Society of Forest Science
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• v.107 no.2
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• pp.158-165
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• 2018

Reach-average velocity prediction in steep mountain streams is important for understanding fluvial processes and practical applications of erosion control in mountain streams. little studies have been conducted in reach-average velocity, but hydraulic researches have been carried out to examine the relationship between discharge and reach-average velocity in torrent reaches using a relatively large amount of discharge data. In this study, a total of 87 data were measured in 8 torrent reaches. Salt-dilution method was used to estimate discharge. Reach-average velocity was calculated from harmonic mean of travel time that were measured by salt-dilution technique. In order to exlpore the hydraulic relation, both discharge and velocity were non-dimensionalized by using $D_{50}$, $D_{84}$, ${\sigma}_{pro}$ and $IPR_{90}$. It also indicated that ${\sigma}_{pro}$ and $IPR_{90}$ were good variables as roughness height for develop the relationship between non-dimensional discharge and velocity in mountain streams. Generally, reach-average velocity could increase exponentially as discharge increases.

• Korean Journal of Social Welfare
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• v.68 no.2
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• pp.185-211
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• 2016

This study analyzes key word networks of the papers which are published at Korean Journal of Social Welfare issued by Korean Academy of Social Welfare from 1979 to 2015. It aims at investigating the trends of social welfare researches in Korea by dividing the given period into two: 1979-2000 and 2001-2015. It shows the trends in three ways: methodologies, subjects, and intellectual structures. In order to identify intellectual structure, it calculate centrality indices basing on co-appearance frequency of key words. It also derives some values which explain relationship structure of key words by using pathfinder algorithm, and finally visualizes the intellectual structures by using the NodeXL program. Some implications of the findings of these analyses are discussed in the end.

• Archives of design research
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• v.13 no.1
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• pp.75-86
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• 2000

We are facing the era of multi-identities in which locals got emphasized, whereas nations'boundary are breaking off under the expansion of de-bounadarisim. In this trend, local autonomous governments are striving to have foreign competitiveness through reforming their administration, such as adopting management styles of companies. If the purpose of administration is set for developing 'the quality of residents' life', introducing 'design' into administration would be one of the best ways. By adopting this design concept, residents 'happiness index' will be increased so that residents' capability will be consolidated to contribute to the development of the local economy. The purpose of this study is to examine various cases of introducing 'design concept' into administration in local autonomous entities. All the methods of introducing design concept are analysed and the implementation methods are proposed. If local autonomous entities operate the design based administration proposed by this study, and if this is relevant to locals, it will create its unique local image and contribute to increasing 'the quality of residenfs life' as well.

• The Korean Journal of Rheology
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• v.6 no.1
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• pp.30-40
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• 1994

고분자 물질의 신장점도를 측정하기 위하여 설계된 수렴관을 지나는 시험 유체 M1 에대하여 유한요소방법으로 수치모사를 수행하였다. 구성방정식은 세 개의 이완시간을 가진 적분형 K-BKZ모형을 사용하였다. 신장변형이 지배적이고 변형속도가 매우 큰 흐름에 대하 여 실험적 방법으로 측정이 가능한 범위까지 수치모사를 수행하였다. 두 개의 압력 측정꼬 지 사이의 벽면 압력차에 대하여 압력 신호로 측정한 실험값을 수치모사결과와 비교하였다. 걷보기 전단속도가 매우 큰 1300s-1에 이르는 높은 유속의 전 실험범위에 대하여 안정된 수 치해를 얻을수 있었다. 3$0^{\circ}C$에서는 모든 실험범위의 유속에서 압력차에 대한 수치모사 결과 가 실험값과 잘일치했다. 21$^{\circ}C$에서는 0.1$\times$10-3m3/s보다 낮은 유속범위에서 실험값과 일치하 는 결과를 얻었으나 그보다 높은 유속에서 실험값과 일치하는 결과를 얻었으나 그보다 높은 유속에서 실험값과 다른 경향의 결과를 얻었다. 이것은 낮은 온도 높은 유속 조건에서 M1 유체의 성질이 불안정하고 또한 그러한 조건의 실험에서 발생한 압력 측정꼭지 부근의 기포 들이 정확한 압력측정에 영향을 끼쳤기 때문이다. 수치모사 결과로부터 얻은 압력과 응력분 포로부터 수렴관 유변측정기의 유동특성을 밝힐수 있었다. 이는 실험적 방법을 통해서는 얻 기 어려운 결과들로서 중요한의미를 가진다. 특별한 모양을 갖도록 설계된 수렴관을 통과하 는 M1 유체가 중심부근에서 일정한 신장변형속도로 변형됨을 확인할 수 있었으며 수직응력 은 지수적으로 증가하다가 축소부분을 지난 후 매우 장점도를 얻기 위하여 신장변형속도가 일정한 구역이 두 배로 확장된 수렴관이 수치적으로 다루어졌고 이를 통하여 기존의 수렴관 에서 구한 값보다 큰 신장점도를 얻을 수 있었다.

• Journal of Korea Water Resources Association
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• v.34 no.3
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• pp.231-240
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• 2001

The problem of the flocculation basin was induced by installing the pilot plant using tracer test at Yang-Duck water treatment plant in Pohang cite. The flocculation basin model downscaled as 1/20 was made of acryl and evaluated hydraulically by transforming the section of the effluent in the flocculation basin. The optimum section of the effluent was suggested and applied to the plant. The efficiency of the flocculation basin according to improvement was evaluated by the particle counter which can count the number of particles each size fraction. The results of this study are as follows : First, it was desirable to make the retention time as short as possible because the flow and the index value were similar regardless of the retention time. Second, after the modification in Yang-Duck water treatment plant, the problem of destruction of floe was improved and the plant was operated satisfactorily. The hydraulic experiment with tracer test can be applied to the performance evaluation as well as improvement of facility in unit process of existing water treatment plant. Additionally, it can be used to find a design factor in the new water treatment plant.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.310-318
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• 1999

The concentration breakthrough curves were examined to predict mass transfer coefficients of nitrogen and oxygen in adsorption column for design data of PSA process. Experimental breakthrough curves for bulk gas flow were compared with theoretical simulation results. For quantitative analysis of the adsorption, coupled Langmuir isotherm was considered and LDF model was used to describe the mass transfer effect. In the experimental and theoretical results, it was found that mass transfer coefficient was not affected by flow rate but strongly affected by pressure. As a result of this tendency, mass transfer resistance in this system was proved to belong to the macropore diffusion controlling region and the mass transfer coefficients could be expressed by exponential functions of pressure change. The mass transfer coefficients for one component, nitrogen or oxygen, were successfully applied to breakthrough curves for bulk mixed gases. The experimental curves were reasonably in consistent with the theoretical curves and the error time was less than 5 percent.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.104-111
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• 2013

Poymer blends of two degradable aliphatic polyesters, relatively expensive material polylactic acid (PLA) and relatively inexpensive material poly(butylene adipate-co-terephthalate) (PBAT), were used in this study. Three different kinds of modifiers were used with various amounts. Diisocyanate type methylenediphenyl 4,4'-diisocyanate (MDI) and hexamethylene diisocyanate (HDI) were used as modifiers and epoxy type coupling agents also used. The melt flow index (MFI) and dynamic viscoelasticity of various compositions of PLA/PBAT blends were studied. The mechanical property and morphology with respect to the fracture surface of PLA/PBAT blends were also investigated using tensile test and field emission scanning electronic microscopy, respectively. These tests were also used to verify the compatibility of PLA/PBAT and the effect of mechanical properties due to the use of modifiers. Tensile properties of PLA/PBAT blends modified with HDI were improved remarkably.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.4
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• pp.165-173
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• 1998

Analytical solutions to predict the movement rate of submerged mound are derived using the convection coefficient and the joint distribution function of wave heights and periods. Assuming that the sediment is moved onshore due to the velocity asymmetry of Stokes' second order nonlinear wave theory, the micro-scale bedload transport equation is applied to the sediment conservation. The nonlinear convection-diffusion equation can then be obtained which governs the migration of submerged mound. The movement rate decreases exponentially with increasing the water depth, but the movement rate tends to increase as the spectral width parameter, $ u$ increases. In comparison of the analytical solution with the measured data, it is found that the analytical solution overestimates the movement rate. However, the agreement between the analytical solution and the measured data is encouraging since this over-estimation may be due to the inaccuracy of input data and the limitation of sediment transport model. In particular, the movement rates with respect to the water depth predicted by the analytical solution are in very good agreement with the estimated result using the discritization technique with the hindcast wave data.