• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.3
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• pp.223-236
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• 2016

The objective of this study was to construct Italian ryegrass (IRG) dry matter yield (DMY) estimation models in South Korea based on climatic data by locations. Obviously, the climatic environment of Jeju Island has great differences with Korean Peninsula. Meanwhile, many data points were from Jeju Island in the prepared data set. Statistically significant differences in both DMY values and climatic variables were observed between south areas of Korean Peninsula and Jeju Island. Therefore, the estimation models were constructed separately for south areas of Korean Peninsula and Jeju Island separately. For south areas of Korean Peninsula, a data set with a sample size of 933 during 26 years was used. Four optimal climatic variables were selected through a stepwise approach of multiple regression analysis with DMY as the response variable. Subsequently, via general linear model, the final model including the selected four climatic variables and cultivated locations as dummy variables was constructed. The model could explain 37.7% of the variations in DMY of IRG in south areas of Korean Peninsula. For Jeju Island, a data set containing 130 data points during 17 years were used in the modeling construction via the stepwise approach of multiple regression analysis. The model constructed in this research could explain 51.0% of the variations in DMY of IRG. For the two models, homoscedasticity and the assumption that the mean of the residuals were equal to zero were satisfied. Meanwhile, the fitness of both models was good based on most scatters of predicted DMY values fell within the 95% confidence interval.

• The Journal of Information Systems
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• v.29 no.3
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• pp.35-52
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• 2020

Purpose Local governments in each region actively hold local festivals for the purpose of promoting the region and revitalizing the local economy. Existing studies related to local festivals have been actively conducted in tourism and related academic fields. Empirical studies to understand the effects of latent variables on local festivals and studies to analyze the regional economic impacts of festivals occupy a large proportion. Despite of practical need, since few researches have been conducted to predict the number of visitors, one of the criteria for evaluating the performance of local festivals, this study developed a model for predicting the number of visitors through various observed variables using a machine learning algorithm and derived its implications. Design/methodology/approach For a total of 593 festivals held in 2018, 6 variables related to the region considering population size, administrative division, and accessibility, and 15 variables related to the festival such as the degree of publicity and word of mouth, invitation singer, weather and budget were set for the training data in machine learning algorithm. Since the number of visitors is a continuous numerical data, random forest, Adaboost, and linear regression that can perform regression analysis among the machine learning algorithms were used. Findings This study confirmed that a prediction of the number of visitors to local festivals is possible using a machine learning algorithm, and the possibility of using machine learning in research in the tourism and related academic fields, including the study of local festivals, was captured. From a practical point of view, the model developed in this study is used to predict the number of visitors to the festival to be held in the future, so that the festival can be evaluated in advance and the demand for related facilities, etc. can be utilized. In addition, the RReliefF rank result can be used. Considering this, it will be possible to improve the existing local festivals or refer to the planning of a new festival.

• Magazine of the Korea Concrete Institute
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• v.11 no.1
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• pp.209-219
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• 1999

This paper describes an experimental study planned to examine the effects of important design variables which were used in the proposed equation by authors. Fourteen beams and slabs were designed with the variables, such as effective prestress, concrete strength, amount of tendons, amount of bonded reinforcements, loading type, and span/depth ratio. Then, deflections and tendon stresses were measured and compared according to the parametric variations of the selected variables. It was found that the tendon stress increment decreases as the level of effective prestress or the amount of unbonded tendons and bonded reinforcements increases. Also, the contributions of concrete strength, and loading type were observed to affect on the tendon stresses. However, the stress increments of unbonded tendon were minimal alt high values of span/depth in contrast with the ACI code.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.76-86
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• 1998

Effects of processing variables and MAPP (maleic anhydride polypropylene) coupling agent on the properties of composite were discussed for turbulent-air-mixed woodfiber-polypropylenefiber composites. In this research, density, composition ratio, and mat moisture content were established as processing variables, and emulsified MAPP prepared by direct pressure method was incorporated as the coupling agent. And the turbulent air mixer, which was improved in function through alteration of our previous fiber mixer, was used to mix wood fibers and polypropylene fibers. At the addition level of 1% MAPP, based on oven-dried wood fiber weight, woodfiber-polypropylenefiber composites generally showed enhanced the physical and mechanical properties. And composites with low to medium densities of 0.6 to 0.8g/$cm^3$ greatly increased in these property values than with high densities of 1.0g/$cm^3$ or more by adding 1 % MAPP. Thus, MAPP addition was thought to be an effective way of enhancing properties for nonwoven web composites. At the mat moisture contents of 5 to 20%, however, the physical and mechanical properties were not enhanced by adding 1% MAPP. In the composites containing 15% polypropylene fibers, the lowest thickness swelling and water absorption values were observed at the 1% MAPP level. The addition of more than 1% MAPP had the adverse effect on the physical and mechanical properties of composites.

• Korean journal of food and cookery science
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• v.29 no.2
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• pp.169-175
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• 2013

The purpose of this study was to provide the basic information necessary to efficiently run a coffee shop. It comparatively analyzes the relative importance and satisfaction of side menu selection characteristics through analyses on customer importance-satisfaction when selecting a side menu as well as their usage behavior of the side menu at coffee shops. According to reason price the analysis result on the differences in the coffee shop side menu importance and satisfaction, there was a difference because the importance of selecting a side menu was higher for the attributes of taste, health, packing & appearance, economics and personnel service compared to satisfaction among which the price of a side menu was found to be the top priority for improvement. The significance of coffee shop side menu for the respondents prior to usage as well as their satisfaction after usage was evaluated in order to comparatively analyze the relative importance and achievement of each characteristic through the IPA. The result indicated that the variables positioned in the Concentrate Here area (II) were related to economic feasibility such as reasonable price, appropriate price of set menu, telecommunication company affiliated service and coupon usage and point accumulation. As for the Keep up the Good Work area (I), there were many variables regarding personnel service including taste of side menu, blending with coffee, clean packing, clean packaging, staff's side menu knowledge, staff's quick response, staff's politeness and staff's sincere response. As for the variables in the Low Priority area (III), health variables on health such as nutritional value, eco-friendly food materials and calories were observed.

• Korean Journal of Occupational Health Nursing
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• v.15 no.2
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• pp.144-152
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• 2006

Purpose: This study was conducted to understand the effects of daily hassle stress on the psycho-social health of male workers in manufacturing industry. Methods: Daily hassle stress and psycho-social health in manufacturing industry workers were estimated by using the Daily Hassles Scale for Korea Workers (DHS-KW) and general health questionnaire (GHQ), respectively. Results: The subjects were 553 male workers who had never been occupationally exposed to hazardous chemicals, were mean age 39.6 years and mean work duration was 15.66 years. DHS-KW total mean score had significantly higher in young ages (twenties and thirties ages), office workers, managers and daytime workers than other groups. GHQ total mean scores were significantly higher in un-married, daytime and overtime workers than others. DHS-KW and GHQ score correlated that they were negative correlation with age and working years, but was positive correlation with working hours and overtime work. The significant correlation between DHS-KW and GHQ were observed almost variables of DHS-KW and GHQ except a domestic and daily problem in DHS-KW variables. Domestic and daily problems were only significantly correlated with anxiety and insomnia of GHQ variables. Conclusion: This study indicated that physical health was associated with work condition and psychsocial health was mainly associated with domestic and daily problems of DHS-KW variables. Thus, the study on Daily Hassles stress and related with work stress should be further investigated for the comprehensive health program including stress management and coping behavior.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.435-444
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• 2017

This study investigated differences between job satisfaction and professionalism by job-related variable and analyzed the effects of job-related variables and job professionalism on job satisfaction among a total of 144 beauty salon workers in Busan and Ulsan. The main results are as follows. First, a difference between job satisfaction and professionalism was found by average monthly income and environmental satisfaction. Second, in terms of correlations with variable, job professionalism revealed static correlation with average monthly income, employment period and environmental satisfaction while job satisfaction showed static correlation with average monthly income, environmental satisfaction and job professionalism. In employment period, a significant difference was observed. Third, regarding the influence of variables on job satisfaction, job satisfaction became higher as average and job professionalism increased. In particular, job professionalism was the highest in terms of exploratory power. So a plan for allowing beauticians to improve confidence in professionalism and job satisfaction was presented.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.267-268
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• 2015

One of the long-standing problems in modern astronomy is the curious division of globular clusters (GCs) into two groups, according to the mean period (<$P_{ab}$>) of type ab RR Lyrae variables. In light of the recent discovery of multiple populations in GCs, we suggest a new model explaining the origin of the Sandage period-shift and the difference in mean period of type ab RR Lyrae variables between the two Oosterhoff groups. In our models, the instability strip in the metal-poor group II clusters, such as M15, is populated by second generation stars (G2) with enhanced helium and CNO abundances, while the RR Lyraes in the relatively metal-rich group I clusters like M3 are mostly produced by first generation stars (G1) without these enhancements. This population shift within the instability strip with metallicity can create the observed period-shift between the two groups, since both helium and CNO abundances play a role in increasing the period of RR Lyrae variables. The presence of more metal-rich clusters having Oosterhoff-intermediate characteristics, such as NGC 1851, as well as of most metal-rich clusters having RR Lyraes with the longest periods (group III) can also be reproduced, as more helium-rich third and later generations of stars (G3) penetrate into the instability strip with further increase in metallicity. Therefore, although there are systems where the suggested population shift cannot be a viable explanation, for the most general cases, our models predict that RR Lyraes are produced mostly by G1, G2, and G3, respectively, for the Oosterhoff groups I, II, and III.

• Archives of design research
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• v.17 no.3
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• pp.179-188
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• 2004

Recently, design has emerged as a key factor of successful product development. This study reviewed the elements of form with a view point of addressing and defining the elements of aesthetics and how they influence consumer aesthetic response. Though past researches related to form aesthetics reported that form aesthetics exist as a single element with other sub-elements, this research made further investigations into form aesthetics and reported that form aesthetics in product design can be broadly divided into form aesthetics and content aesthetics. Empirical studies on each category was undertaken and from the results obtained, it was concluded that typicality is a dominant element in content aesthetics while rhythm is a dominant element in form aesthetics. Also, the study investigated the effect of conditional variables such as price and brand hierarchy on each category and it was observed that both content and form aesthetics elements are affected by conditional variables such as price and brand hierarchy, Furthermore, the study reports that both content and form aesthetics elements are mutually correlated and both categories affect user's aesthetics response. It is intended that the results obtained from this work will contribute to theoretical knowledge of aesthetic elements and can be put to use by product design and manufacturing companies.

• Journal of Korean Academy of Nursing
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• v.49 no.4
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• pp.398-410
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• 2019

Purpose: This study used a system dynamics methodology to identify correlation and nonlinear feedback structures among factors affecting adolescent cyberbullying victims (CV) in Korea and to construct and verify a simulation model. Methods: Factors affecting CV were identified by reviewing a theoretical background in existing literature and referencing various statistical data. Related variables were identified through content validity verification by an expert group, after which a causal loop diagram (CLD) was constructed based on the variables. A stock-flow diagram (SFD) using Vensim Professional 7.3 was used to establish a CV model. Results: Based on the literature review and expert verification, 22 variables associated with CV were identified and the CLD was prepared. Next, a model was developed by converting the CLD to an SFD. The simulation results showed that the variables such as negative emotions, stress levels, high levels of conflict in schools, parental monitoring, and time spent using new media had the strongest effects on CV. The model's validity was verified using equation check, sensitivity analysis for timestep and simulation with 4 CV adolescent. Conclusion: The system dynamics model constructed in this study can be used to develop intervention strategies in schools that are focused on counseling that can prevent cyberbullying and assist in the victims' recovery by formulating a feedback structure and capturing the dynamic changes observed in CV. To prevent cyberbullying, it is necessary to develop more effective strategies such as prevention education, counseling and treatment that considers factors pertaining to the individual, family, school, and media.