• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3196-3206
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• 2021

For the Korean design of the PCCS (passive containment cooling system) in an innovative PWR, the overall thermal resistance around a condenser tube is dominated by the heat transfer coefficient of steam condensation on the exterior surface. It has been reported, however, that the calculated heat transfer coefficients by thermal-hydraulic system codes were much lower than measured data in separate effect tests. In this study, a new empirical model of steam condensation in the presence of a noncondensable gas was implemented into the MARS-KS 1.4 code to replace the conventional Colburn-Hougen model. The selected correlation had been developed from condensation test data obtained at the JERICHO (JNU Experimental Rig for Investigation of Condensation Heat transfer On tube) facility, and considered the effect of the Grashof number for naturally circulating gas mixture and the curvature of the condenser tube. The modified MARS-KS code was applied to simulate the transient response of the containment equipped with the PCCS to the large-break loss-of-coolant accident. The heat removal performances of the PCCS and corresponding evolution of the containment pressure were compared to those calculated via the original model. Various thermal-hydraulic parameters associated with the natural circulation operation through the heat transport circuit were also investigated.

• Geomechanics and Engineering
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• 제19권3호
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• pp.283-293
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• 2019

Evaluating the stability of the excavation face of the cross-river shield tunnel with good accuracy is considered as a nonlinear and multivariable complex issue. Understanding the stability evaluation method of the shield tunnel excavation face is vital to operate and control the shield machine during shield tunneling. Considering the instability mechanism of the excavation face of the cross-river shield and the characteristics of this engineering, seven evaluation indexes of the stability of the excavation face were selected, i.e., the over-span ratio, buried depth of the tunnel, groundwater condition, soil permeability, internal friction angle, soil cohesion and advancing speed. The weight of each evaluation index was obtained by using the analytic hierarchy process and the entropy weight method. The evaluation model of the cross-river shield construction excavation face stability is established based on the idea point method. The feasibility of the evaluation model was verified by the engineering application in a cross-river shield tunnel project in China. Results obtained via the evaluation model are in good agreement with the actual construction situation. The proposed evaluation method is demonstrated as a promising and innovative method for the stability evaluation and safety construction of the cross-river shield tunnel engineerings.

• 천문학회지
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• 제53권6호
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• pp.139-147
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• 2020

The sunspot area is a critical physical quantity for assessing the solar activity level; forecasts of the sunspot area are of great importance for studies of the solar activity and space weather. We developed an innovative hybrid model prediction method by integrating the complementary ensemble empirical mode decomposition (CEEMD) and extreme learning machine (ELM). The time series is first decomposed into intrinsic mode functions (IMFs) with different frequencies by CEEMD; these IMFs can be divided into three groups, a high-frequency group, a low-frequency group, and a trend group. The ELM forecasting models are established to forecast the three groups separately. The final forecast results are obtained by summing up the forecast values of each group. The proposed hybrid model is applied to the smoothed monthly mean sunspot area archived at NASA's Marshall Space Flight Center (MSFC). We find a mean absolute percentage error (MAPE) and a root mean square error (RMSE) of 1.80% and 9.75, respectively, which indicates that: (1) for the CEEMD-ELM model, the predicted sunspot area is in good agreement with the observed one; (2) the proposed model outperforms previous approaches in terms of prediction accuracy and operational efficiency.

• 한국직업건강간호학회지
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• 제31권1호
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• pp.31-41
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• 2022

Purpose: This study aimed to identify the effects of organizational culture, organizational silence, and organizational commitment on the intention of retention as perceived by nurses Methods: The research model was designed on the basis of the PROCESS Macro model 6 proposed by Hayes. The participants were 142 nurses from general hospitals. Measurements included the scales of organizational culture, organizational silence, organizational commitment, and intention of retentione. Data were analyzed using descriptive statistics, Pearson's correlation coefficient analysis, and Hayes's PROCESS macro method for mediation. Results: Retention intention showed a significantly positive correlation with relationship-orientated culture (r=.32, p<.001), innovation-orientated culture (r=.30, p<.001), and organizational commitment (r=.48, p<.001). However retention intention showed a significantly negative correlation with organizational silence (r=-.42, p<.001). Furthermore, organizational silence and commitment had a mediating effect on the relationship between organizational culture and intention of retention. Conclusion: The impact of organizational culture on intention of retention in general hospitals was mediated by organizational silence and organizational commitment. Considering the mediating effects of organizational silence and organizational commitment on the relationship between nursing organizational culture and retention intention, a strategy should be developed to enhance organizational commitment and weaken organizational silence by strengthening related and innovative nursing culture.

• 유통과학연구
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• 제21권12호
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• pp.23-34
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• 2023

Purpose: The purpose of this study is to identify factors affecting satisfaction as well as the intention of Gen Z customers to reorder food online in the context of a crisis. Research design, data and methodology: Data for this cross-sectional study were collected via the Internet by conducting an online survey of 652 Gen Z respondents, aged 15-25, in the south of Vietnam and using a convenience sampling method. To analyse the reliability of the scales, SPSS was used to run Cronbach's alpha. Then, SmartPLS was used to assess the measurement model, including variable reliability and validity, convergent validity, and discriminant validity of the proposed model, as well as test the hypotheses with partial least squares structural equation modelling (PLS-SEM). Results: Social influence, price value, and convenience all have a positive effect on satisfaction and repurchase intention. Satisfaction not only plays a critical role in mediating the relationship between social influence, price value, convenience and repurchase intention but also has a positive impact on repurchase intention towards buying food online. Conclusions: This study was successful in identifying the factors of repurchase intention in a crisis setting among Gen Z customers by developing a theoretical research model via literature to complete a brief Theory of Planned Behaviour model. This study also took an innovative approach to earlier ones by demonstrating not just the significant effect of social influence on satisfaction and repurchase intention, but also by identifying critical variables that managers should focus on increasing and improving management.

• Steel and Composite Structures
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• 제49권6호
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• pp.645-666
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• 2023

Due to the steadily declining supply of natural coarse aggregates, the concrete industry has shifted to substituting coarse aggregates generated from byproducts and industrial waste. Oil palm shell is a substantial waste product created during the production of palm oil (OPS). When considering the usage of OPSC, building engineers must consider its uniaxial compressive strength (UCS). Obtaining UCS is expensive and time-consuming, machine learning may help. This research established five innovative hybrid AI algorithms to predict UCS. Aquila optimizer (AO) is used with methods to discover optimum model parameters. Considered models are artificial neural network (AO - ANN), adaptive neuro-fuzzy inference system (AO - ANFIS), support vector regression (AO - SVR), random forest (AO - RF), and extreme gradient boosting (AO - XGB). To achieve this goal, a dataset of OPS-produced concrete specimens was compiled. The outputs depict that all five developed models have justifiable accuracy in UCS estimation process, showing the remarkable correlation between measured and estimated UCS and models' usefulness. All in all, findings depict that the proposed AO - XGB model performed more suitable than others in predicting UCS of OPSC (with R², RMSE, MAE, VAF and A_15-index at 0.9678, 1.4595, 1.1527, 97.6469, and 0.9077). The proposed model could be utilized in construction engineering to ensure enough mechanical workability of lightweight concrete and permit its safe usage for construction aims.

• 한국항공운항학회지
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• 제32권2호
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• pp.100-111
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• 2024

This study was conducted to explain airport users' acceptance intention for untact smart devices being introduced at Incheon Airport. Based on the technology acceptance model, perceived usefulness and ease of use influenced attitudes and intention to use. It was verified whether it was affecting the effect. In addition, variables proposed in innovation diffusion theory were selected to verify exogenous variables that affect perceived usefulness and ease of use, which serve as key independent variables in the technology acceptance model. Research results show that perceived usefulness has a high level of positive influence on attitude, whereas perceived ease of use has a low influence and does not show a statistically significant influence. In addition, it was confirmed that most variables of the innovation diffusion theory had no effect on usefulness and ease of use. This means that the key variable in the spread and use of untact smart devices at airports is the perception of usefulness, which means that resistance to accepting new technology is not high.

• 한국산업융합학회 논문집
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• 제27권4_1호
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• pp.769-780
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• 2024

For an organization to survive and prosper, it is essential to continuously develop innovative products by proactively anticipating consumers' implicit requirements. The Kano model has become more useful since Sireli et al. (2007) and Tontini (2007) introduced a simple equation for determining the importance of characteristics by using the concept of Kano's Potential Customer Satisfaction Coefficient (PCSC). However, although several studies have utilized the PCSC concept to determine the importance of characteristics, it is surprising that the two equations have been accepted without any validation process. This study aims to propose a modified equation using PCSC and to conduct a validity test of the proposed equation, demonstrating its superiority over the previously suggested two equations, The author analysed 26 Kano related articles (27 cases), and the correlation coefficients were compared with those obtained from direct rating importance, which served as a comparative criterion. The results indicate that the proposed equation is valid for assessing characteristic importance and demonstrates significantly higher correlation coefficients with the direct method than those suggested by Tontini (2007) and Siireli et al. (2007). The proposed method offers advantages in terms of accuracy and survey duration over traditional methods that directly ask for relative importance (e.g., AHP by Saaty (1980)). Furthermore, the integration of the Kano model with IPA or QFD could enhance the accuracy and efficiency of research in determining the importance of characteristics.

• 디지털융복합연구
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• 제14권5호
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• pp.137-147
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• 2016

본 논문에서는 학계나 실무에서 주목하는 비즈니스 모델에 관한 두 가지 분석도구를 소개하고, 이를 활용하는 방법에 대해 설명하였다. Osterwalder and Pigneur(2010)가 소개한 '비즈니스 모델 캔버스'는 9개의 구성요소를 갖고 있으며, 한 장에 분석결과를 일목요연하게 정리할 수 있다. Keeley et al.(2013)가 소개한 '10가지 혁신 유형 모델'도 10개의 구성요소를 담고 있으며, 각 요소별로 혁신하는 방법을 제시하였다. 두 기법 모두 가치제안에서 가치창출, 가치전달, 가치확보에 이르기까지 비즈니스 모델이 갖추어야 할 전체 요소를 분석할 수 있다는 장점이 있다. 다만 기존 비즈니스 모델을 혁신할 때, 문제를 해결할 새로운 아이디어를 충분히 제공하지 못하는 단점이 있다. 향후 구성요소별로 다양한 혁신 사례들이 개발되고, 또한 혁신적인 비즈니스 모델의 원형들이 제시된다면, 기업 실무에서 보다 체계적으로 비즈니스 모델 설계나 혁신을 구현할 수 있을 것이다.

• 대한토목학회논문집
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• 제39권3호
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• pp.409-418
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• 2019

건설프로젝트 성공을 위해 건설기업은 지식기반 정보화와 세계화의 가속화에 따른 환경변화에 적응하고 대처할 수 있는 건설프로젝트에 참여하는 구성원들의 혁신능력을 중요하게 인식하기 시작했다. 설문은 건설프로젝트 참여구성원을 대상으로 온라인을 이용했다. 최종유효 표본은 254 부며, 실증분석은 구조방정식 모델(Smart-PLS 2.0)을 이용했다. 건설프로젝트 참여구성원의 개인-직무 적합성과 보상시스템에 대한 심리적 주인의식이 혁신행동에 미치는 영향 관계는 다음과 같다. 첫째, 개인-직무 적합성은 심리적 주인의식에 정(+)의 영향을 미쳤다. 둘째, 보상시스템에서 내재적 보상과 외재적 보상은 심리적 주인의식에 정(+)의 영향을 미쳤다. 셋째, 심리적 주인의식은 혁신행동에 정(+)의 영향을 미쳤다. 끝으로, 심리적 주인의식의 매개효과는 개인-직무 적합성과 보상시스템에 대해 매개효과는 발휘되지 않았다. 이상의 결과는 경영자로 하여금 건설프로젝트 참여구성원의 혁신행동을 유발하기 위해 심리적 주인의식의 중요성을 인식하고 개인-직무 적합성 및 보상프로그램의 개발을 통해 건설프로젝트 조직 활성화 모델을 구축할 필요가 있다.