• Land and Housing Review
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• v.13 no.4
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• pp.73-89
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• 2022

With the spread of COVID-19, the role of parks has been emphasized. Under the quarantine guidelines, including social distancing, people are visiting parks as a safe place. In line with these changes, parks need to be studied as pandemic adaptation measures according to their physical and location characteristics. This study aims to explore the potential of linear parks with accessibility and pass way functions based on the characteristics of surrounding land uses. The case study area was selected from Yeonnam-dong to Yeomni-dong of the Gyeongui Line Forest Park, and the area was divided into 4 sections based on the administrative boundary and surrounding land uses. Multiple regression models were adopted in each section using the total number of de facto population as a dependent variable and factors affecting external activities including COVID-19 as independent variables. The results show that first, the more diverse the interaction between commercial facilities and linear parks, the greater the impact of the pandemic. Second, where various commercial facilities are concentrated people respond more sensitively to short-term weather changes than seasonal ones. This study indicates that there are differences in the use of linear parks according to the surrounding land uses. In addition, it suggests that the linear park has potential as a means to overcome the Pandemic crisis of the city and to increase equity in access to green areas.

• Journal of The Korean Association For Science Education
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• v.42 no.2
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• pp.201-214
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• 2022

The purpose of this study is to examine the characteristics of model of the experiment in students' open inquiry. The research is a reinterpretation of the data collected from the performance of a three-year research project under the theme of 'school science inquiry' the perspective of model of the experiment. The inquiry activities of a focus group made up of four students have been recorded seven times. The recorded files and transcribed copies were analyzed according to interpretive methods. Students' activities were divided into three modeling of the experiment units, considering the modeling unit that includes the process of starting from the problem until it gets solved. The results of the study include illuminating the dynamic process and characteristics of modeling of the experiment and discussing its educational meaning as a distributed cognitive system at each modeling unit. First, students, instruments, and the primitive form of calculation represented by the interaction between them turned out to be important factors in the distributed cognitive system that constitutes model of the experiment. Second, in the early stages, non-verbal activities were carried out in which students became familiar with instruments, and verbal quantitative signs were created when the activities were sufficiently carried out. The generated quantitative signs became a source of data and confidence that can be referenced in subsequent activities. Third, the specialization of instrumentalization occurred, and factors that were important in inquiry, such as variable control, appeared. The results of the study provide new implications for science education research and education, which have been centered on explanatory models, by unfolding the characteristics of model of the experiment that have not been noticed in science education through students' inquiry.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1423-1431
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• 2022

Volatility is one of the variables that the Black-Scholes model requires for option pricing. It is an unknown variable at the present time, however, since the option price can be observed in the market, implied volatility can be derived from the price of an option at any given point in time and can represent the market's expectation of future volatility. Although volatility in the Black-Scholes model is constant, when calculating implied volatility, it is common to observe a volatility smile which shows that the implied volatility is different depending on the strike prices. We implement supervised learning to target implied volatility by adding V-KOSPI to ease volatility smile. We examine the estimation performance of KOSPI200 index options' implied volatility using various Machine Learning algorithms such as Linear Regression, Tree, Support Vector Machine, KNN and Deep Neural Network. The training accuracy was the highest(99.9%) in Decision Tree model and test accuracy was the highest(96.9%) in Random Forest model.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1059-1066
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• 2021

In Korea, the importance of marine activities is great, and automatic weather observation facilities are operating on land to investigate abnormal weather phenomena caused by industrialization; however, the number of facilities at sea is insufficient. Marine survey ships are operated to establish marine safety information, but there are many places where marine survey ships are difficult to access and operating costs are high. Therefore, a small, unmanned vessel capable of marine surveys must be developed. The sail has a significant impact on the sailing performance, so much research has been conducted. In this study, the camber effect, which is a design variable of the twin curvy sail known to have higher aerodynamic performance than existing airfoil shapes, was investigated. Flow analysis results for five cases with different camber sizes show that the lift coefficient is highest when the camber size is 9%. Curvy twin sails had the highest lift coefficient at an angle of attack of 23° because of the interaction of the port and starboard sails. The port sail had the highest lift coef icient at an angle of attack of 20°, and the starboard sail had the lowest lift coef icient at an angle of attack of 15°. In addition, the curvy twin sail had a higher lift coefficient than NACA 0018 at all angles of attack.

• Journal of the Korea Society of Computer and Information
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• v.27 no.6
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• pp.157-165
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• 2022

The purpose of this study was to determine whether unstable surface core exercise is more effective than stable surface core exercise on improving functional movement and balance and reducing pain in sedentary female workers with backpain. Participants were randomly assigned to an unstable surface core exercise(UEG; n=10) or a stable surface core exercise(SEG; n=10) group. They participated in the given exercise for 8 weeks. FMS, Y-Balance and VAS were measured before and after the participation in exercise, which were subjected to a repeated-measures ANOVA. In the case of a significant interaction between time and group, paired sample t-tests were conducted for a post hoc analysis within each subject group. Results indicated that FMS of the UEG had a significant effect on HS (p<.01), ASLR (p<.05) and TS(p<.001), but not for other variables. YBT did not show a significant effect for any variable (AT, PL, PM, TS), although the main effect of time was significant in both subject groups. VAS had a significant effect only in the UEG(p<.001). Our findings indicate that compared to SEG, UEG is more effective for improving functional movement and reducing pain, but not for improving balance, in sedentary female workers with backpain.

• Journal of Service Research and Studies
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• v.12 no.4
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• pp.19-29
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• 2022

This study is a descriptive survey using a self-reported survey method to understand the effect of language and non-verbal communication of medical service providers on customer satisfaction through Lapport and to determine the degree of impact on Lapport by adjusting perceived service authenticity. The data collection period was from April 5 to April 30, 2021. Using the convenience sampling method, data were collected from users of medical institutions located in Busan and Gyeongsangnam-do, and a total of 306 valid questionnaires were used as statistical analysis data. The collected data were analyzed using the IBM SPSS statistics version 25.0 and AMOS 20.0 programs through a coding process. In the results of this study, it was found that the language and non-verbal communication of medical service providers influenced customer satisfaction through Lapport, and the perceived service authenticity in the relationship between each variable acts as a moderating effect. Considering that the language and non-verbal factors of the medical service provider are important in the interaction between the medical service provider and the hospital user, the medical service provider should take full account of the language and non-verbal factors and help the medical institution communicate with the hospital user.

• Korean small business review
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• v.41 no.4
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• pp.65-86
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• 2019

This study empirically analyzed how the elements of entrepreneurship and the fear of entrepreneurial failure influence entrepreneurial intention with each other in a situation that encourages startups. In particular, the moderating effect of fear of entrepreneurial failure was verified by dividing the fear of entrepreneurial failure into three sub-variables: fear of financial loss, fear of psychological loss, and fear of career loss. As a result, it was found that proactiveness and risk-taking had a positive effect on entrepreneurial intention, but innovativeness did not. Fear of entrepreneurial failure(all of sub-variables) was found to have no significantly moderating effect on the relationship between entrepreneurship and entrepreneurial intention. Therefore it seemed to have a negative effect as a independent variable. However, considering the regression coefficient(β) is positive or negative depending on the interaction terms of the sub-variables of fear of entrepreneurial failure and the entrepreneurship, it could be inferred that the moderating effect could be positive or negative. Based on this research results, a sophisticated entrepreneurship education program to inspire entrepreneurship and lower the fear of failure is needed in order to promote startups. And at the same time, a social safety net construction plan to reduce the fear of entrepreneurial failure needs to be prepared.

• Korean Journal of Culture and Social Issue
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• v.13 no.1
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• pp.115-136
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• 2007

A trustworthy counseling relationship is an important variable for an effective counseling progression and counseling goal achieving. This study was designed to examine effects of ambivalence over emotional expressiveness and counselor perception on working alliance. Objects of this study were clients in university counseling centers, counseling centers for adolescents and private counseling institutes. Clients were asked to answer an ambivalence over emotional expressiveness questionnaire, a counselor perception questionnaire and a working alliance questionnaire. Total 97 cases were collected and the data was analysed by multiple regression method. The results were as followed; ambivalence over emotional expressiveness was not significantly related to working alliance. However, counselor perception was significantly related to working alliance. That is, the more positively counselors were perceived, the better working alliance was. Effects of counselor perception's sub-factors on working alliance were also found; attractiveness was significantly related to working alliance but trustworthiness and expertness were not. An interaction of ambivalence over emotional expressiveness and counselor perception on working alliance was also significant. As for those clients who were high at the ambivalence over emotional expressiveness, working alliance was increased in case they had positive counselor perception. In conclusion, it is not personality factors but that counselor perception that makes the difference in working alliance

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.156-168
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• 2024

Purpose: The trend of highway traffic accidents shows a repeating pattern of increase and decrease, with the fatality rate being highest on highways among all road types. Therefore, there is a need to establish improvement measures that reflect the situation within the country. Method: We conducted accident severity analysis using Random Forest on data from accidents occurring on 10 specific routes with high accident rates among national highways from 2019 to 2021. Factors influencing accident severity were identified. Result: The analysis, conducted using the SHAP package to determine the top 10 variable importance, revealed that among highway traffic accidents, the variables with a significant impact on accident severity are the age of the perpetrator being between 20 and less than 39 years, the time period being daytime (06:00-18:00), occurrence on weekends (Sat-Sun), seasons being summer and winter, violation of traffic regulations (failure to comply with safe driving), road type being a tunnel, geometric structure having a high number of lanes and a high speed limit. We identified a total of 10 independent variables that showed a positive correlation with highway traffic accident severity. Conclusion: As accidents on highways occur due to the complex interaction of various factors, predicting accidents poses significant challenges. However, utilizing the results obtained from this study, there is a need for in-depth analysis of the factors influencing the severity of highway traffic accidents. Efforts should be made to establish efficient and rational response measures based on the findings of this research.

• Korean Journal of Environment and Ecology
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• v.38 no.4
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• pp.426-433
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• 2024

In this study, to estimate the effects of plant-induced surface area increase and physiological activity on fine dust purification, a control group was set up. We utilized both foliage plants (Spathiphyllum wallisii) and artificial plants (shaped like Spathiphyllum wallisii) to measure and compare the purification time for fine dust. The results showed that the time required for fine dust purification in each experimental group decreased by 57-64% for Type AP and 31-32% for Type P compared to the control group. Subsequently, using a Linear Mixed Model (LMM), we tested the interaction between time and each experimental group, revealing statistically significant interactions between surface area increase and time(PM10 : t=3.123, p<0.05, PM2.5 : t=3.180, p<0.05), as well as physiological activity and time(PM10 : t=4.065, p<0.05, PM2.5 : t=4.307, p<0.05), indicating the presence of interactions between each factor and the time variable. Finally, we estimated the efficiency of fine dust purification by plant factors through nonlinear regression analysis. Compared to the control group without purification factors (Type C), it was estimated that surface area increase shortened the purification time by 1.40 times and physiological activity by an average of 1.95 times, resulting in a total 2.74 times shorter purification time. Based on these results, we hypothesized that physiological activity(transpiration and absorption) has a greater impact on fine dust purification than surface area increase(biosorption). Accordingly, we emphasize the importance of vegetation management practices such as pruning and irrigation management in green spaces aimed at fine dust purification.