• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.272-290
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• 2003

In this study a model for the drying process in paper production plants was developed based on the mass and heat balances around drying cycles. Relationships for the heat transfer coefficients between the web and the air as well as between the drying cylinder and the web were extracted from the closed-loop plant operation data. It was found that the heat transfer coefficients could be represented effectively in terms of moisture content, basis weight and reel velocity. The effectiveness of the proposed model was illustrated through numerical simulations. From the comparison with the operation data, the proposed model represents the paper plant being considered with sufficient accuracy.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1078-1082
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• 2005

In this study, the run-up height and reflection property on slopes of S-berm and smooth slopes breakwaters are investigated by laboratory experiment. The run-up height analyzed the effect of reflection coefficient, surf similarity parameter. Measured reflection coefficients of smooth slope breakwaters are compared with those of S-berm breakwater with variable widths. In general, measured coefficients of S-berm breakwaters are smaller than those of smooth slope breakwaters.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1311-1315
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• 2009

Understanding of the hydraulics of flow is very important to support the management of river. The cross-sectional area, average velocity, flow depth and discharge can be regarded as a power function each other. In this paper the flow of Bocheong stream basin is experimentally studied. The correlation analysis was performed between observed hydraulic factors by the power type function. The constants resulted from the correlation analysis were calculated by the geomorphologic characteristics of the watershed using the power type function. The correlation coefficients between the hydraulic factors were appeared close to unit having strong correlationship. The two conditions of equality of the continuity equation were analysed, and the conditions were found to be good results. From these results the observed hydraulic data of Bocheong stream basin can be concluded as a reliable data. The correlation coefficients between the parameters of the hydraulic characteristics and geomorphologic factors were found to be close to unit.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.5
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• pp.53-61
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• 2003

In this study a model for the drying process in paper production plants was developed based on the mass and heat balances around drying cycles. Relationships for the heat transfer coefficients between the web and the air as well as between the drying cylinder and the web were extracted from the closed-loop plant operation data. It was found that the heat transfer coefficients could be represented effectively in terms of moisture content, basis weight and reel velocity. The effectiveness of the proposed model was illustrated through numerical simulations. From the comparison with the operation data, the proposed model represents the paper plant being considered with sufficient accuracy.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.122-125
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• 1998

In this article, a reduction method for nominal variables is presented and its use illustrated. Factor analysis model (FAM) generally enables us to reduce variables having interval or ratio scale based on their correlation coefficients. We developed an extensive method that makes FAM applicative to the case of nominal variables which does not give correlation coefficients, but only the degree of association. Cramer's V coefficient is a well-established measure that provides the strength of association for nominal variables with a range of [0,1]. When Cramer's V coefficient can logically substitute for correlation coefficient, FAM would be extensively used for reduction of nominal variables.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1111-1115
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• 2008

The relative magnitudes of the individual terms of the momentum equation are analyzed and compared by the analytical methods in open channel flow. The temporal variations of each term(local acceleration term, convective acceleration term, pressure force term, gravity force term, and friction force term) are analyzed for the influence factors to runoff expressed by the parameters of the momentum equation, stream slopes and roughness coefficients. The magnitudes of each term vary with the channel characteristics, especially when the roughness coefficients are dominant or for the mild stream slopes the pressure term can not be negligible. As a result of the characteristics of momentum equation in open channel flow, the acceleration terms are very small compared with the other terms. The magnitudes of local acceleration and convective acceleration offsets each other. The peak time of each term except the gravity term coincides with inflection point of the hydrograph rising limb each other.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1585-1588
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• 2008

조도계수를 산정하는데는 수많은 방법이 있다. 그러나 일반적으로 하천정비기본계획(또는 댐실시설계보고서 등 각종보고서)의 조도계수를 그대로 적용하거나, 기준이 모호한 조도계수정보테이블(Roughness Coefficients Information Table)을 이용하고 있다. 하천의 이용은 시대에 따라 달라지며 최근 하천정비 사업의 급속한 진행으로 하천정비기본계획의 조도계수 또한 하천형상을 정확히 반영하기 어려운 현실이다. 소하천의 경우 하천정비기본계획 마저 수립되어 있지 않은 경우도 있어 조도계수로 인한 하천모의에 영향은 매우 크다. 따라서 소하천의 정확한 모의를 위해서는 소하천에 적합한 조도계수 산정방법에 대한 비교분석이 선행되어야 한다. 그러므로 본 연구에서는 실제 소하천에서 획득한 실측자료로부터 다양한 조도계수 산정방법을 적용하여 그 결과를 비교 분석하였다.

• Journal of the Korean Home Economics Association
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• v.33 no.4
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• pp.49-64
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• 1995

The purpose of this study was to develop the Daily Hassles Scale for children in Korea. The subject were 444 children of 184 fourth graders and 260 sixth graders selected form five elementary schools in Seoul(217 male and 227 female). A questionnaire consisting of 90-item daily hassles scale, demographic questions, and some additional questions was used as a methodological instrument. statistics used for data analysis were X2, cramer's V, factor analysis, multi-regression, Pearson's r, Cronbach's α. The major findings of this study were as follows. 1) 87 items of the 90-item scale were acceptible through item discriminant method. The discriminant coefficients of the items(Cramer's V) ranged form .28 to .73. 2) 6 factors(parents, home environment, friends, studies, teachers & school, the surroundings) were extracted from factor analysis. Multi-regression analysis conducted to reduce the length of scale have drawed 42 items for 'the Daily Hassles Scale for Children in Korea'. The correlation between this scale and the Quality of Life Scale(Olson & Barnes, 1982) was conducted to test the criterion-related validity, and the coefficient was significant(r=-.52, p<.001).3) Finally, reliability coefficients(Cronbach'α) of this scale was. 85.

• Journal of the Korean Home Economics Association
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• v.31 no.2
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• pp.41-54
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• 1993

The purpose of this study was to develop 「the Self-Esteem Inventory」(SEI). The 2,451 subjects were selected randomly from 4, 5 and 6th grades of elementary schools and the first and second grades of middle schools in the city to Taegu. Factor analysis, Pearson's r, Cramer's V, and Cronbach's αwere conducted for the statistical analysis. It was found that (1) Factor analysis showed that SEI consisted of 4 factors (global, social-peers, home-parents, and school-academics), (2) The discriminant coefficients of the items (Cramer's V)ranged from 0.25 to 0.71, (3) The reliability coefficients of the scale (Cronbach's α) ranged from 0.69 to 0.84, and (4) The correlation coeffcients of the SEI with RSES and CSEI ranged from 0.47 to 0.78.

• Journal of Korea Water Resources Association
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• v.34 no.5
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• pp.551-560
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• 2001

The research estimated the roughness coefficients for the reach of Hwawon-Goryeonggyo-Hyeongpung stage stations in the Nakdong River through hydraulic channel routing. The data needed were only stage data from the three stations and river cross section data. Stage-discharge relations were determined from the computed discharges by the channel routing. They are better than the previous stage-discharge relations from direct measurements. Discharge computation errors from stage errors were analyzed and a simple method was suggested to limt reach lengths from prohibiting large errors from lateral inflows.