• Geomechanics and Engineering
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• 제23권1호
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• pp.61-69
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• 2020

The uniaxial compressive strength (UCS) of rock is a basic parameter in underground engineering design. The disadvantages of this commonly employed laboratory testing method are untimely testing, difficulty in performing core testing of broken rock mass and long and complicated onsite testing processes. Therefore, the development of a fast and simple in situ rock UCS testing method for field use is urgent. In this study, a multi-function digital rock drilling and testing system and a digital core bit dedicated to the system are independently developed and employed in digital drilling tests on rock specimens with different strengths. The energy analysis is performed during rock cutting to estimate the energy consumed by the drill bit to remove a unit volume of rock. Two quantitative relationship models of energy analysis-based core drilling parameters (ECD) and rock UCS (ECD-UCS models) are established in this manuscript by the methods of regression analysis and support vector machine (SVM). The predictive abilities of the two models are comparatively analysed. The results show that the mean value of relative difference between the predicted rock UCS values and the UCS values measured by the laboratory uniaxial compression test in the prediction set are 3.76 MPa and 4.30 MPa, respectively, and the standard deviations are 2.08 MPa and 4.14 MPa, respectively. The regression analysis-based ECD-UCS model has a more stable predictive ability. The energy analysis-based rock drilling method for the prediction of UCS is proposed. This method realized the quick and convenient in situ test of rock UCS.

• 한국가스학회지
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• 제24권5호
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• pp.47-55
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• 2020

위험물 사고는 해당 물질의 누출에 그치지 않고, 초기대응이 부적합한 경우, 화재, 폭발로 이어져 그 피해규모가 확대될 위험이 크다. 하지만 4차 산업혁명과 빅데이터 시대의 대두가 논의되고 있는 시점에서, 새로운 기법들에 바탕한 위험물 사고의 체계적인 분석은 시도되지 못하고, 단편적인 통계 수집에 그치고 있는 것이 아쉬운 실정이다. 본 연구에서는 지난 11년간(2008~2018) 축적된 소방청 위험물 화재사고 데이터를 대상으로 기계학습에 기반한 분석을 진행하였다. Text mining 분석을 통해 분석한 자료를 시각화하여 나타내었고, 아울러 위험물 화재사고 데이터에 존재하는 주요 인자를 이용해 피해규모 예측모델의 개발 가능성을 회귀분석 방법을 적용하여 탐색하였다.

• 복식문화연구
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• 제23권2호
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• pp.161-175
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• 2015

The purpose of this study is to examine the impact of perceived sustainability management fit of SPA brands on consumer purchase intention. A survey was conducted targeting women in their 20s and 30s from April 27th to May 6th 2013, and a total of 350 questionnaires were used in the final analysis. Frequency analysis, reliability analysis, factor analysis, ANOVA, simple regression analysis and multiple regression analysis were carried out using SPSS ver 21.0. The results of this study are as follows. First, fit of all three areas- economic, ecological and social-of sustainability management activities have a significant impact on consumer perception on sustainability activities. Second, perceived sustainability activities by SPA brands are found to have a positive effect on brand attitude, brand trust and consumer satisfaction. Third, brand attitude and consumer satisfaction forged by perceived sustainability activities by SPA brands have a positive impact on consumers' purchase intention. Based on the result of this study, the following marketing implications can be suggested. First, SPA brands need to be more active in all three area of sustainability activities while coming up with measures for differentiated social sustainability activities. Second, SPA brands need to meet their primary obligation by providing consumers with quality products at a reasonable price. Third, SPA brands need to recognize the potential value of sustainability activities as a driver of a longstanding relationship with consumers as well as long-term profit and value creation, leading to a great financial performance.

• 한국항해항만학회지
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• 제37권6호
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• pp.673-680
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• 2013

본 연구는 요트체험 활동 참여자들의 몰입도가 만족도 및 자아존중감에 미치는 영향에 관한 것으로서 우리나라 요트문화 및 레저산업의 대중화 실현에 기초자료를 제공하는데 그 목적이 있다. 이러한 연구 목적을 달성하기 위해 부산 울산 경남지역 주민을 대상으로 해양레저 아카데미 및 해양레저 체험 프로그램에 참여한 경험이 있는 대상자 총 428명을 모집단으로 선정하여 설문조사를 실시하였으며, 자료처리 방법은 빈도분석, 신뢰도분석, 타당도분석, 단순회귀분석, 다중회귀분석을 사용하였다. 이상과 같은 연구방법 및 자료분석의 결과를 통해 도출된 결론은 다음과 같다. 첫째, 요트체험 참가자들의 몰입도는 만족도에 정적인 영향을 미치는 것으로 나타났다. 둘째, 요트체험 참가자의 몰입도는 자아존중감(일반요인, 가정요인, 직장요인, 사회요인)에 정적인 영향을 미치는 것으로 나타났다. 셋째, 요트체험 참가자의 만족도는 자아존중감(일반요인, 가정요인, 직장요인, 사회요인)에 정적인 영향을 미치는 것으로 나타났다.

• 한국프랜차이즈경영연구
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• 제11권4호
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• pp.7-15
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• 2020

Purpose: The purpose of this study is to clarify the role of decoupling between job characteristics, innovation behavior, and innovation resistance in order to seek ways for companies to survive and grow continuously through innovation activities in various uncertain situations. Research design, data and methodology: A total of 263 valid questionnaires were collected and used for analysis for employees working at the company. For the analysis, simple and multiple regression analysis, and 3-step mediated regression analysis were conducted using SPSS 24.0 and AMOS 24.0. Results: First, it was found that skill variety, task identity, autonomy, and feedback increase decoupling, and decoupling increases innovation resistance. In addition, it was confirmed that decoupling had a mediating effect between job characteristics and innovation resistance excluding task significance. Finally, it was found that task significance and feedback increase innovation behavior, and decoupling and task identity increase innovation resistance, but feedback can alleviate innovation resistance. Conclusions: As a result of the analysis, the fact that job characteristics excluding task importance have a positive effect on decoupling means that there are two sides of job characteristics perceived by employees. In other words, it means that the results of analysis on the jobs that the company assigns to its members may not be effective. In addition, decoupling, a phenomenon that seems to be accepting on the outside, but perceives that it is negative on the inside, means that there is a possibility to reject innovation. Therefore, prior to carrying out innovation activities, companies should give clear job specifications and meanings for the job and give them autonomy when assigning jobs to their members. In order to provide appropriate feedback, the company must design, operate, and provide feedback. It was found that there was a need to review the overall effectiveness. In addition, efforts such as strengthening corporate-level fairness, maintaining psychological contracts, and realizing authentic leadership should be preceded to reduce decoupling.

• Membrane and Water Treatment
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• 제7권2호
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• pp.127-141
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• 2016

Electrodialysis (ED) is known to be a useful membrane process for desalination, concentration, separation, and purification in many fields. In this process, it is desirable to work at high current density in order to achieve fast desalination with the lowest possible effective membrane area. In practice, however, operating currents are restricted by the occurrence of concentration polarization phenomena. Many studies showed the occurrence of a limiting current density (LCD). The limiting current density in the electrodialysis process is an important parameter which determines the electrical resistance and the current utilization. Therefore, its reliable determination is required for designing an efficient electrodialysis plant. The purpose of this study is the development of a predictive model of the limiting current density in an electrodialysis process using response surface methodology (RSM). A two-factor central composite design (CCD) of RSM was used to analyze the effect of operation conditions (the initial salt concentration (C) and the linear flow velocity of solution to be treated (u)) on the limiting current density and to establish a regression model. All experiments were carried out on synthetic brackish water solutions using a laboratory scale electrodialysis cell. The limiting current density for each experiment was determined using the Cowan-Brown method. A suitable regression model for predicting LCD within the ranges of variables used was developed based on experimental results. The proposed mathematical quadratic model was simple. Its quality was evaluated by regression analysis and by the Analysis Of Variance, popularly known as the ANOVA.

• 한국농공학회지
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• 제44권7호
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• pp.64-73
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• 2002

This study was performed to evaluate effects of physical characteristics of both watershed and reservoir on nutrient-chlorophyll relationship in Korean reservoirs. Simple linear models were developed with published data in Korea including 415 reservoirs and 11 multi-purpose dams, and physico-chemical parameters of reservoirs and characteristics relationship of models were analyzed. Theoretical residence time in Korean reservoirs was strongly correlated with the ratio of TA/ST (drainage area + surface area / storage volume) in the logarithmic function. As a result of monthly nutrients-chlorophyll-a regression analysis, significant Chl-a-TP relationship appeared during May～July. The high Chl-a yields per total phosphorus appeared during this time (R$\^$2/=0.51, p<0.001, N= 1088). Chlorophyll-a demonstrated much stronger relationship with TP. than TN. Seasonal algal-nutrient coupling were closely related with N:P ratio in the reservoir water, and it was, in turn, dependent on the monsoon climatic condition (precipitation). Based on the results of regression analysis and high N:P ratio, a major limiting factor of algal growth appeared to be phosphorus during this time. Unlikely TA/ST ratio, DA/SA ratio (drainage area f surface area) was likely to influence directly on the nutrient-Chl-a relationship, indicating that if storage volume and inflowing water volume were the same, algal biomass could be developed more in reservoirs with large surface area. Thus, DA/SA ratio seemed to be an important factor to affect the development of algal biomass in Korean reservoirs. With low determination coefficient of TP-Chl-a relationship, our findings indicated not only nutrient (phosphorus) but also other physical factors, such as DA/SA ratio, may affect algal biomass development in Korean reservoirs, where actual residence time appears to be more closely related to reservoir surface area rather than storage volume.

• 한국병원경영학회지
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• 제24권2호
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• pp.12-22
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• 2019

Purposes: The purpose of this study was to examine the association between risk behaviors and smoking in Korean adolescents. Methods: This study used data from online survey of youth health behavior in 2017. Data from a total of 54,411 people (27,139 male, 27,272 female) were included in the analysis. chi-square test, simple logistic regression, multiple logistic regression were performed using SAS 9.4. Findings: Multiple logistic regression analysis showed that risk behaviors such as drinking alcohol experience, sexual experience, drug use experience and high caffeine energy drinks intake experience had a significant effect on smoking. Adolescents with drinking experience were more likely to smoking than those who had no experience(OR=8.58, 95% CI: 7.67~9.60). Adolescents with sexual experience were more likely to smoking than those who had no experience(OR=4.47, 95% CI: 3.91~5.11). Adolescents with drug use experience were more likely to smoking than those who had no experience(OR=2.32, 95% CI: 1.63~3.32). Also, adolescents with high-caffeine energy drinks intake experience were more likely to smoking than those who had no experience(OR=1.37, 95% CI: 1.23~1.53). Practical Implications: All the risk behaviors were significantly associated with smoking rates. Results of this study suggest that physicians and health workers in medical institutions and health centers should simultaneously serve education and consultation for the smoking cessation as well as for the prevention of risk behaviors.

• Journal of Hospice and Palliative Care
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• 제15권2호
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• pp.88-98
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• 2012

목적: 본 연구는 국내 의료사회복지사의 영성과 상태 희망과의 관계를 파악하여, 효과적인 영성 및 상태희망을 증진시키는 개입의 기초자료를 제공하기 위해 수행되었다. 방법: 2011년 9월 1일부터 9월 30일까지 국내 의료사회복지사 102명을 대상으로, 상태희망척도(State Hope Scale)와 한국형 영성척도(Spirituality Scale)를 사용하여 수행되었다. 자료분석은 SPSS WIN ver. 17.0 프로그램을 이용하여, 기술통계, t-test, ANOVA, Seffee's 사후검정, Pearson's correlation, Simple regression을 사용하였다. 결과: 대상자의 영성수준은 종교에 따른 유의한 차이를 보였고, 상태희망의 평균점수는 6.36/8.00, 영성수준은 3.80/5.00이었다. 영성은 상태희망과 유의미한 순상관관계를 보였다(P<0.001). 상태희망의 하위영역(경로사고, 주도사고)과 영성의 하위영역(삶의 의미와 목적, 자비심, 내적자원, 자각, 연결성, 초월성)간의 상관관계는 모두 유의미한 정적 상관관계(P<0.01)를 보였다. 결론: 의료사회복지사의 영성과 상태희망 간에는 유의미한 순상관관계가 있으며, 영성이 상태희망에 긍정적 영향을 미치는 것이 확인되었다. 영적 감수성 지향의 사회사업 접근을 위한 더 많은 후속연구가 요구된다.

• Geomechanics and Engineering
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• 제28권4호
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• pp.397-404
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• 2022

Accurate prediction of the undrained shaft resistance is essential for robust design of bored piles in undrained condition. The undrained shaft resistance is calculated using the undrained adhesion factor multiplied by the undrained cohesion of the soil. However, the available correlations to predict the undrained adhesion factor have been developed using simple regression techniques and the accuracy of these correlations has not been thoroughly assessed in previous studies. The lack of the assessment of these correlations made it difficult for geotechnical engineers to select the most accurate correlation in routine designs. Furthermore, limited attempts have been made in previous studies to use advanced data mining techniques to develop simple and accurate correlation to predict the undrained adhesion factor. This research, therefore, has been conducted to fill these gaps in knowledge by developing novel and robust correlation to predict the undrained adhesion factor. The development of the new correlation has been conducted using the multi-objective evolutionary polynomial regression analysis. The new correlation outperformed the available empirical correlations, where the new correlation scored lower mean absolute error, mean square error, root mean square error and standard deviation of measured to predicted adhesion factor, and higher mean, a20-index and coefficient of correlation. The correlation also successfully showed the influence of the undrained cohesion and the effective stress on the adhesion factor. Hence, the new correlation enhances the design accuracy and can be used by practitioner geotechnical engineers to ensure optimized designs of bored piles in undrained conditions.