• The Korean Journal of Applied Statistics
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• v.29 no.7
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• pp.1445-1458
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• 2016

This paper derives a correlation coefficient using detrended cross-correlation analysis (DCCA) method for 59 regional temperature series for 40 years from 1976 to 2015. The average temperature, maximum temperature, and minimum temperature series for 4 year units are analyzed; consequently, we estimated that a temperature correlation exists between the two regions during the unit period where the correlation coefficient is greater than or equal to 0.9; subsequently, we construct a network linking the two regions. Based on network theory, average path length, clustering coefficient, assortativity, and modularity were derived. As a result, it was found that the temperature network satisfies a small-worldness property and is a network having assortativity and modularity.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.253-255
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• 2010

복잡계 과학의 발달에 따라 많은 사회 네트워크들이 분석되고 있다. 우리는 연결선수, 중간성(betweenness), 결집계수와 같은 링크수를 중심으로 네트워크의 구조적 분석에서 나아가 복잡한 네트워크 속에서 핵심 되는 중심 모듈을 찾아 분석하였다. K-core알고리즘은 복잡계 네트워크를 가중치가 낮은 링크와 노드를 단계적으로 제거하여 복잡한 네트워크의 의미를 분석함에 있어 핵심이 되는 모듈을 얻는데 용이하다. 이에 소설, 영화, 과학 교과서, 단백질 상호작용 네트워크와 같은 다양한 분야에 이 알고리즘을 직접 적용해보았다. 그 결과, 각기 복잡한 네트워크로부터 핵심이 되는 모듈을 찾아낼 수 있었고, 전체 네트워크에서는 발견하기 힘든 유용한 정보들을 도출할 수 있음을 확인하였다. 본 연구에서 k-core 알고리즘을 통해 핵심 네트워크를 구축하여 유용한 정보를 도출할 수 있는 가능성을 제시하였다.

• Membrane Journal
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• v.8 no.3
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• pp.157-169
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• 1998

The effects of solvents (DMAc, NMP, 1,4-dioxane) and nonsolvents ($H_2O$, Methanol, n-hexane) on the morphology of 6FDA-p-TeMPD polyimide membrane, prepared by the wet phase inversion method, were studied. In the polymer/solvent/nonsolvent ternary system, the binodal curve, the coagulation value and the relative light transmission were measured, and the solubility parameter difference was calculated. The onset state and rate of liquid-liquid alemixing were predicted and the morphology of membrane was analyzed. It is found that the finger-like pores are formed within discontinuous polymer nodules when the binoclal curve is close to the polymer-solvent (P-S) axis, the coagulation value is small, the reduction of light transmission is easy to occur and the order of solubility parameter difference ($\Delta \delta_{i-j}$) is $\Delta \delta_{S-NS} > \Delta \delta_{P-NS} > \Delta \delta_{P-S}$. The dense skin with small nodules and the sponge type sublayer with macrovoid are formed in the case that the binodal curve is distant from the P-S axis, the onset time of liquid-liquid demixing is long and the order of $\Delta \delta_{i-j}$ is $\Delta \delta_{P-NS} >(\Delta \delta_{S-NS} < > \Delta \delta_{P-S})$. The thick layer of fine nodule coagulation and loosely grown sublayer of nodules appear when the binodal curve is distant from the P-S axis, the onset time of liquid-liquid demixing is very long and the order of $\Delta \delta_{i-j}$가 $\Delta \delta_{S-NS} > (\Delta \delta_{P-NS}$\lessgtr$ > (\Delta \delta_{P-NS} < >)\Delta \delta_{P-S}$ ).

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.420-428
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• 2010

The advancement of the Science for complex systems enables the analysis of many social networks. We constructed and analyzed a Korean movie star network as one of social networks, based on the 100 Korean movie selection for a main data source. Until now, the research trend has been the structural analysis of network, focused on link numbers, such as degree, betweenness and clustering coefficient. But it is time that the research is not limited by the structural analysis of networks only. Rather, the research goal should be aimed to an information analysis, performed by identifying and analyzing central modules that are regarded as the core of complex networks, using k-core analysis method. In this research, we constructed a network of movie stars who have appeared in 100 Korean movie selection, provided by Korean movie database, also we analyzed its core modules with and without weights, and the trend of seasonal expansion of the network. We expect our findings can be used as the basic data applicable to a model for understanding of the expansion and evolution of networks.

• Journal of the Korean Wood Science and Technology
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• v.16 no.2
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• pp.1-41
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• 1988

For the purpose of utilizing the sawdust having poor combining properties as board raw material and resulting in dimensional instability of board, polypropylene chip (abbreviated below as PP chip) or oriented PP thread was combined with sawdust particle from white meranti(Shorea sp.). The PP chip was prepared from PP thread in length of 0.25, 0.5, 1.0 and 1.5 cm for conventional blending application. Thereafter, the PP chip cut as above was combined with the sawdust particle by 3, 6, 9, 12 and 15% on the weight basis of board. Oriented PP threads were aligned with spacing of 0.5, 1.0 and 1.5cm along transverse direction of board. The physical and mechanical properties on one, two and three layer boards manufactured with the above combining conditions were investigated. The conclusions obtained at this study were summarized as follows: 1. In thickness swelling, all one layer boards combined with PP chips showed lower values than control sawdustboard, and gradually clear decreasing tendendy with the increase of PP chip composition. Two layer board showed higher swelling value than one layer board, but the majority of boards lower values than control sawdustboard. All three layer boards showed lower swelling values than control sawdustboard. 2. In the PP chip and oriented thread combining board, the swelling values of boards combining 0.5cm spacing oriented thread with 1.0 or 1.5cm long PP chip in 12 and 15% by board weight were much lower than the lowest of one or three layer. 3. In specific gravity of 0.51, modulus of rupture of one layer board combined with 3% PP chip showed higher value than control sawdustboard. However, moduli of rupture of the boards with every PP chip composition did not exceed 80kgf/cm2, the low limit value of type 100 board, Korean Industrial Standard KS F 3104 Particleboards. Moduli of rupture of 6%, 1.5cm-long and 3% PP chip combined boards in specific gravity of 0.63 as well as PP chip combined board in specific gravity of 0.72 exceeded 80kgf/$cm^2$ on KS F 3104. Two layer boards combined with every PI' chip composition showed lower values than control sawdustboard and one layer board. Three layer boards combined with.1.5cm long PP chip in 3, 6 and 9% combination level showed higher values than control sawdustboard, and exceeded 80kgf/$cm^2$ on KS F 3104. 4. In modulus of rupture of PP thread oriented sawdustboard, 0.5cm spacing oriented board showed the highest value, and 1.0 and 1.5cm spacing oriented boards lower values than the 0.5cm. However, all PP thread oriented sawdustboards showed higher values than control saw-dustboard. 5. Moduli of rupture in the majority of PP chip and oriented thread combining boards were higher than 80kgf/$cm^2$ on KS F 3104. Moduli of rupture in the boards combining longer PP chip with narrower 0.5cm spacing oriented thread showed high values. In accordance with the spacing increase of oriented thread, moduli of rupture in the PP chip and oriented thread combining boards showed increasing tendency compared with oriented sawdustboard. 6. Moduli of elasticity in one, two and three layer boards were lower than those of control sawdustboard, however, moduli of elasticity of oriented sawdustboards with 0.5, 1.0 and 1.5cm spacing increased 20, 18 and 10% compared with control sawdustboard, respectively. 7. Moduli of elasticity in the majority of PP chip and oriented thread combining boards in 0.5, 1.0 and 1.5cm oriented spacing showed much higher values than control sawdustboard. On the whole, moduli of elasticity in the oriented boards combined with 9% or less combination level and 0.5cm or more length of PP chip showed higher values than oriented sawdustboard. The increasing effect on modulus of elasticity was shown by the PP chip composition in oriented board with narrow spacing. 8. Internal bond strengths of all one layer PP chip combined boards showed lower values than control sawdust board, however, the PP chip combined boards in specific gravity of 0.63 and 0.72 exceeded 1.5kgf/$cm^2$, the low limit value of type 100 board and 3kgf/$cm^2$, type 200 board on KS F 3104, respectively. And also most of all two, three layer-and oriented boards exceeded 3kgf/$cm^2$ on KS F. 9. In general, screw holding strength of one layer board combined with PP chip showed lower value than control sawdustboard, however, that of two or three layer board combined with PP chip did no decreased tendency, and even screw holding strength with the increase of PP chip composition. In the PP chip and oriented PP thread combining boards, most of the boards showed higher values than control sawdustboard in 9% or less PP chip composition.