• Computers and Concrete
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• 제21권5호
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• pp.559-567
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• 2018

In this study alkali activation of Electric Arc Furnace Slag (EAFS) is studied with a comprehensive test program. Three different silicate moduli (1-1,5-2), three different sodium concentrations (4%-6%-8%) for each silicate module, two different curing conditions (45%-98% relative humidity) for each sodium concentration, two different curing temperatures ($400^{\circ}C-800^{\circ}C$) for each relative humidity condition and two different curing time (6h-12h) for each curing temperature variables are selected and their effects on compressive strength was evaluated then regression equations using multiple linear regressions methods are fitted. And then to select the best regression models confirm with using the variables, the regression models compared between itself. An Artificial Neural Network (ANN) models that use silicate moduli, sodium concentration, relative humidity, curing temperature and curing time variables, are formed. After the investigation of these ANN models' results, ANN and multiple linear regressions based models are compared with each other. After that, an explicit formula is developed with values of the ANN model. As a result of this study, the fluctuations of data set of the compressive strength were very well reflected using both of the methods, multiple linear regression with quadratic terms and ANN.

• Ocean Systems Engineering
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• 제10권1호
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• pp.111-129
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• 2020

A simplified algorithm is proposed for fast estimation of the material quantities required for the construction of rubble-mound breakwaters. The proposed algorithm is able to employ only the data available at feasibility study phase such as the maximum draught of the design ship selected to transport the cargos to the harbor despite, because at the feasibility phase, information for the planned harbor is likely to be very limited. A linear-constant waterdepth model together with a proposed section configuration for the breakwaters, which is customary for harbors, is considered to calculate the quantity of materials. The numerical simulation of the wave characteristics has been verified using the recorded wave data collected by a buoy installed near the Neka harbor in Caspian Sea waters. A case study has been also applied to four harbors to validate the proposed algorithm. The estimated weights using the proposed linear-constant and multi-linear waterdepth models were compared using the bathymetry maps and layouts of these harbors. A computer program, written in QBasic language, has been developed to simulate the wave characteristics and to estimate the material quantities needed to construct a rubble-mound breakwater. The obtained results show that taking into account the acceptable accuracies normally applied to the feasibility study and conceptual design phases, the proposed algorithm is sufficiently accurate and highly effective for the conceptual estimation of materials' quantities of breakwaters in the feasibility study phase of harbor projects.

• 대한기계학회논문집
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• 제11권2호
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• pp.205-213
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• 1987

본 논문에서는 비압축 선형 점탄성재료를 원통체로 모델화하여 열하중에 대한 거동을 점유적 시간증분과정을 적용하여 수치해를 제시하고 원통체를 제작실험하여 변 형과 비파괴검사를 통해 측정하여 비교검토하였다. 또한 이론적 수치해와 시편과의 안전율을 각 파괴기준(failure criteria)에 적용하여 비파괴검사결과와 비교하였다.

• 한국환경과학회지
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• 제32권3호
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• pp.161-171
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• 2023

The present study evaluated growth factors affecting oak community plantations through literature review and a field survey. Specifically, 41 related literature sources were analyzed and field surveys were conducted to collect growth data. Previous studies were analyzed to identify variables with high frequency of use. The frequency of use was in the order of tree size > environment > planting density > forest age. Analysis of factors impacting height and diameter growth revealed that the growth rate of species other than Quercus variabilis was negative in the field survey. This may be because of differences between the actual trees planted and specifications in the construction drawings, which may be attributed to the site conditions and decisions made by the project subject during construction. Furthermore, simple linear regression analysis was conducted with time, height at planting, density, and species code as the independent variables and growth rate as the dependent variable. A strong positive linear correlation was noted between height and diameter. This work builds a foundation for developing a forest restoration model and simulation program based on a regression model derived from the four variables tested.

• 지역사회간호학회지
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• 제14권2호
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• pp.287-298
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• 2003

The purpose of the study was to develop an integrated prevention program to strengthen elders self-care capability and to examine its effectiveness on their psychological condition. This study used one group pre- and post-test design. Subjects were 85 elderly residents (over 65 years of age) who lived alone, and received free basic medical care and social welfare services in a rural community in Korea. Subject eligibility criteria for this study were to an elders who 1) is not currently taking any anti-depressant medication 2) is able to communicate, and 3) agrees to participate in this study. The integrated program was composed of horticulture, reminiscence, and friendship activities. Twelve sessions were provided for 12 weeks in community-based partnerships to achieve better outcomes. The intervention was case-managed by a public health nurse and aided by six volunteers. The main outcome variable was depression, which was assessed by using 15 items selected from the Geriatric Depression Scale-short form Korean version. Socio-demographic characteristics, functional status, and satisfaction with social support were used as covariates. Results showed that there was a significant intervention effect at post-intervention time point compared to pre-intervention time point(E.S. 0.94). Multiple linear regression analysis showed significant interaction effects between intervention and satisfaction with social support. These findings must be interpreted within the context that an effects of an integrated program could be more synergistically increased when social support factor is considered in the program. A community-based integrated prevention program of depression is effective for vulnerable rural elderly. It is suggested that randomized controlled trials within community setting for better methodological strength as well as multi-level outcomes on community need to be conducted in future.

• 대한간호학회지
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• 제48권2호
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• pp.182-194
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• 2018

Purpose: This study aimed to estimate the effects of a health mentoring program on fasting blood sugar, total cholesterol, triglyceride, physical activity, self care behavior and social support changes among community-dwelling vulnerable elderly individuals with diabetes. Methods: A non-equivalent control group pre-post-test design was used. Participants were 70 community-dwelling vulnerable elderly individuals with diabetes. They were assigned to the experimental (n=30) or comparative (n=30) or control group (n=28). The experimental group participated in the health mentoring program, while the comparative group participated in health education program, the control group did not participate in any program. Data analyses involved a chi-square test, Fisher's exact test, a generalized linear model, and the Bonferroni correction, using SPSS 23.0. Results: Compared to the control group, the experimental and comparative groups showed a significant decrease in fasting blood sugar, total cholesterol, and triglyceride. Compared to the comparative and control groups, the experimental group showed significant improvement in self care behavior. However, there were no statistical differences in physical activity or social support among the three groups. Conclusion: These findings indicate that the health mentoring program is an effective intervention for community-dwelling vulnerable elderly individuals with diabetes. This program can be used as an efficient strategy for diabetes self-management within this population.

• 한국콘텐츠학회논문지
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• 제21권7호
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• pp.171-180
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• 2021

대중매체에 노출된 장소는 잠재여행객에게 호기심과 기대를 형성하여 행동을 유도하며 대중매체를 통해 반복적으로 노출된 장소는 시청자에게 영향을 미친다. TV 프로그램 중에서 가장 큰 파급력을 지닌 장르는 드라마이고, 드라마와는 다른 특성의 몰입을 제공하는 리얼리티프로그램은 시청자의 여행지 선정에 영향을 준다. 관광지처럼 시장에서 평가되지 못하는 대상의 가치추정에 주로 이용되는 것이 가상가치평가법(CVM)이다. 본 연구는 CVM을 활용하여 드라마와 여행예능프로그램을 대상으로 촬영지의 경제적 가치평가를 실시 한 후 두 프로그램 촬영지의 연구결과를 비교분석 하였다. 드라마와 여행예능 프로그램 촬영지 지불의사측정을 위해 선형로짓과 로그로짓분석을 실시하였으며 지불가능금액을 도츨하였다. 연구결론은 드라마와 여행예능 프로그램 촬영지를 방문하는데 필요한 여행비용이 증가할수록 방문의사는 감소하였다. 드라마와 여행예능 프로그램 촬영지 방문시에 지불가능한 금액이 일반 당일여행 평균소비금액보다 높았으며 드라마가 여행예능프로그램 촬영지 방문보다 지불가능한 금액이 모두 높았다.

• 사회복지연구
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• 제41권3호
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• pp.163-184
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• 2010

자활사업은 국민기초생활보장제도가 도입된 이래로 우리나라 빈곤정책의 주요한 변화를 가져왔다. 자활사업 참여자의 특성은 성별, 연령, 학력과 같이 시간에 따라 크게 변하지 않는 속성을 지닌다. 자활성과와 관련한 수급자의 특성을 연구함으로써 주요 대상 집단을 설정하고 이에 따라 자활사업의 효과적인 제공도 가능하다. 이 연구는 GLM분석을 통해 자활사업 참여자의 특성이 자활성과에 미치는 영향을 주효과와 상호작용효과에 의해 분석하였다. 분석결과, 학력, 자활사업유형, 지역, 소득, 연령, 보호아동유무, 성별 변인이 정서적 자활성과와 경제적 자활성과에 대해 영향을 미친 것으로 드러났다. 자활사업 참여자의 특성에 따라 자활성과에서 차이가 있으므로 자활사업의 프로그램을 참여자의 특성에 맞게 세분화하여 제공할 필요가 있다.

• Journal of Mechanical Science and Technology
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• 제14권1호
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• pp.19-29
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• 2000

A viscoelastic finite element analysis is presented to investigate residual stresses occurred in a laminated cylindrical shell during cure. An incremental viscoelastic constitutive equation that can describe stress relaxation during the cure is derived as a recursive formula which can be used conveniently for a numerical analysis. The finite element analysis program is developed on the basis of a 3-D degenerated shell element and the first order shear deformation theory, and is verified by comparing with an one dimensional exact solution. Viscoelastic effect on the residual stresses in the laminated shell during the cure is investigated by performing both the viscoelastic and linear elastic analyses considering thermal deformation and chemical shrinkage simultaneously. The results show that there is big difference between viscoelastic stresses and linear elastic stresses. The effect of cooling rates and cooling paths on the residual stresses is also examined.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.121-144
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• 2005

In this paper, we propose unconstrained and constrained posynomial Geometric Programming (GP) problem with negative or positive integral degree of difficulty. Conventional GP approach has been modified to solve some special type of GP problems. In specific case, when the degree of difficulty is negative, the normality and the orthogonality conditions of the dual program give a system of linear equations. No general solution vector exists for this system of linear equations. But an approximate solution can be determined by the least square and also max-min method. Here, modified form of geometric programming method has been demonstrated and for that purpose necessary theorems have been derived. Finally, these are illustrated by numerical examples and applications.