• Journal of the Korea Institute of Building Construction
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• v.17 no.6
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• pp.535-544
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• 2017

This paper analyzes the relations between design errors, prevented by building information modeling (BIM)-based design validation, and their impacts in order to identify critical consideration factors for implementing BIM-based design validation in architecture, engineering, and construction (AEC) projects. More than 800 design errors detected by BIM-based design validation in two BIM-based projects in South Korea are categorized according to their causes (illogical error, discrepancy, and missing item) and work types (structure, architecture, and mechanical, electrical, and plumbing (MEP)). The probabilistic relations among the independent variables, including the causes and work types of design errors, and the dependent variables, including the project delays, cost overruns, low quality, and rework generation that can be caused by these errors, are analyzed using logistic regression. The characteristics of each design error are analyzed by means of face-to-face interviews with practitioners. According to the results, the impacts of design error causes in predicting the probability values of project delays, cost overruns, low quality, and rework generation were statistically meaningful.

• Tribology and Lubricants
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• v.33 no.6
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• pp.269-274
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• 2017

Currently, fuel efficiency becomes one of critical issues for automotive industries as concerns about environmental and energy problems grow. In an automatic transmission of an automobile, a drag torque due to a viscous drag of a fluid between friction and clutch plates is one of factors that degrade fuel economy. In this work, the drag torque characteristics of a wet clutch was experimentally investigated with respect to rotational speed, temperature of automatic transmission fluid (ATF), and gap between friction and clutch plates. The experimental results showed that drag torque increases to a certain level, and then decrease to the steady state value with increasing rotational speed. This behavior may be associated with two-phase flow of air and ATF at gap between friction and clutch plates. Also, it was found that the maximum drag torque value decreased as ATF viscosity decreases with increasing temperature. However, it was shown that the point at which the maximum drag torque occurs was not significantly affected by the ATF temperature. In addition, maximum drag torque was found to decrease as the gap between friction and clutch plates increased from 0.1 mm to 0.2 mm. Furthermore, it was observed that the generation of maximum drag torque was delayed as the gap increased. The outcomes of this work are expected to be helpful to gain a better understanding of drag torque characteristic of a wet clutch, and may therefore be useful in the design of wet clutch systems with improved performance.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.394-394
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• 2009

Water solubility of conjugated polymers may offer many applications. Potential applications of water-soluble conjugated polymers include the polymer light-emitting diode and new materials for nano and micro hollow-capsules, and bio- or chemo-sensors. We synthesized neutral polyfluorenes containing bromo-alkyl groups by the palladium catalyzed Suzuki coupling reaction. Bromo-alkyl side groups in neutral polyfluorenes were quaternized by tri-methyl amine solution. The electrochemical and optical properties of water-soluble conjugated polymers are discussed. This novel synthesized water-soluble conjugated polymers were used as a interfacial dipole layer between active layer and metal cathode in polymer solar cell for enhancement of open-circuit voltage (Voc), which is one of the most critical factors in determining device characteristics. We also investigated the device performance of polymer solar cell with different metal cathode such as Al, Ag, Au and Cu. In polymer solar cell, novel cationic water-soluble conjugated polymers were inserted between active layer and high-work function cathode (Al, Ag, Au and Cu).

• Computers and Concrete
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• v.25 no.4
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• pp.311-325
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• 2020

In this research work, the hygrothermal and mechanical buckling responses of simply supported FG sandwich plate seated on Winkler-Pasternak elastic foundation are investigated using a novel shear deformation theory. The current model take into consideration the shear deformation effects and ensures the zero shear stresses on the free surfaces of the FG-sandwich plate without requiring the correction factors "Ks". The material properties of the faces sheets of the FG-sandwich plate are assumed varies as power law function "P-FGM" and the core is isotropic (purely ceramic). From the virtual work principle, the stability equations are deduced and resolved via Navier model. The hygrothermal effects are considered varies as a nonlinear, linear and uniform distribution across the thickness of the FG-sandwich plate. To check and confirm the accuracy of the current model, a several comparison has been made with other models found in the literature. The effects the temperature, moisture concentration, parameters of elastic foundation, side-to-thickness ratio, aspect ratio and the inhomogeneity parameter on the critical buckling of FG sandwich plates are also investigated.

• Steel and Composite Structures
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• v.25 no.2
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• pp.157-175
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• 2017

The novelty of this work is the use of a new displacement field that includes undetermined integral terms for analyzing thermal buckling response of functionally graded (FG) sandwich plates. The proposed kinematic uses only four variables, which is even less than the first shear deformation theory (FSDT) and the conventional higher shear deformation theories (HSDTs). The theory considers a trigonometric variation of transverse shear stress and verifies the traction free boundary conditions without employing the shear correction factors. Material properties of the sandwich plate faces are considered to be graded in the thickness direction according to a simple power-law variation in terms of the volume fractions of the constituents. The core layer is still homogeneous and made of an isotropic material. The thermal loads are assumed as uniform, linear and non-linear temperature rises within the thickness direction. An energy based variational principle is employed to derive the governing equations as an eigenvalue problem. The validation of the present work is checked by comparing the obtained results the available ones in the literature. The influences of aspect and thickness ratios, material index, loading type, and sandwich plate type on the critical buckling are all discussed.

• Journal of the Korean Dietetic Association
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• v.30 no.2
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• pp.95-111
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• 2024

The Smart Hazard Analysis Critical Control Point (HACCP) management system, which integrates information technology (IT) to automate and analyze big data, has been introduced into school food services. This study investigated the job performance, job satisfaction, and job stress of employees in school food services using Smart HACCP. Data were collected via questionnaires from 350 employees in school food services who utilized Smart HACCP and worked in Gyeonggi-do or Incheon. The questionnaire included general information, workplace characteristics, HACCP education status, job performance, and job satisfaction according to the use of Smart HACCP, and general job stress. The responses showed that 92.3% of the participants had received HACCP education in the workplace, and 66.6% understood the content of the education. Among the HACCP process stages, CCP2 (Food Handling and Cooking) and CCP3 (Cooking Completion and Distribution) were the stages at which all participants were using Smart HACCP. CCP3 had the highest percentage (61.4%) of participants who experienced feeling the maximum reduction in their tasks by using Smart HACCP. The Smart HACCP job performance at CCP1 (Inspection) and Smart HACCP job satisfaction were higher in workplaces with 6~10 employees, compared to those with 10≤ employees (both P<0.05). The Smart HACCP job performances at of CP1 (Refrigeration and Freezer Temperature Management) and CP2 (Cleaning and Disinfection of Food Contact Surfaces) were significantly affected by the work area. General job stress was significantly higher in cooks than in cook practitioners, higher in employees with cook certification than in those without it, and higher in employees with work experience (<1 year), compared to those with 5~10 years or 10~15 years' experience. In conclusion, employees' job performance and satisfaction with Smart HACCP need to be enhanced to improve hygiene in school food service. This requires the effective management of their job stress.

• Korean Journal of Comparative Education
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• v.27 no.1
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• pp.247-284
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• 2017

The purpose of this study is to analyze firm's motivation of participating and investing in apprenticeship in Germany and Korea, and to investigate institutional factors influencing firm's motivation. By comparing institutional factors of the two countries, it aims to drawing out policy implications for improving Korean apprenticeship. The main method for data collection was comprehensive literature review on international organizations, each countries' government and research institutes' policy materials, statistical data, research outputs and media resources related to each countries' apprenticeship. Considering whether firm's motivation for participating and investing in apprenticeship is production-oriented or investment-oriented, Germany is more inclined to investment motivation with firm's covering net cost during apprenticeship period. On the other hand, Korea is more inclined toward production orientation with firm's expectation of gaining net profit during the training period. Why is firm's training motivation different in these two countries? The author tried to find the reason from the difference of institutional factors of the countries by dividing institutional factors into 4 categories: context(tripartite relations, legal framework), input (flexibility of the system, government incentive), process(training contents, training duration, quality assurance), and output(completion/retention rate, apprentice's productivity). The key implication from the comparative analysis of institutional factors is that it is necessary to enforce companies to have "accountability" on the minimum critical elements, but also to ensure them to have "autonomy" on the rest of the elements.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.357-364
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• 2012

For this study, real estate brokerage services to customers how to evaluate quality factors and quality factors important for studying about what is preferred. Real estate brokerage service quality factors, the expertise of brokers, dealers sales skills, a sense of responsibility of traders, brokerage firm's position, whether or not participating were chosen franchise. Looking at the findings, and customer service quality factors, the five kinds of real estate brokers a sense of responsibility to be the most important quality factors were analyzed as a favorite, followed by the expertise of brokers, sales skills brokers, brokerage firm's presence, a franchise analysis of whether the order has been participating. As the results of this study, the traders as traders sense of responsibility and expertise and strive to improve, friendly servece and act as an active intermediarv will need to improve sales skills. Continuous promotion of the brokerage firm's position is shown to be critical, franchise affiliated businesses in order to make use of an efficient information network of the Internet is seen to be in need of improvement. This paper, we have experienced a real estate brokerage contracts require customers a service directly to find out whether the data obtained through interviews with the empirical analysis is Therefore, work-related departments of Ministry of Land and brokerage herein with reference to the Association to take measures to Once you have contributed little bit. Brokerage industry and the traders themselves, as well as the competition is to the straight ahead Do not look at a value for the development of brokerage will be constantly working.

• Quality Improvement in Health Care
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• v.4 no.2
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• pp.210-221
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• 1997

Background : Willingness to satisfy patients(WSP) among nurses is essential to promoting patient satisfaction which is a critical component in the quality of health care and its outcomes. This study was carried out to empirically find out the affecting factors of WSP among nurses in hospital settings. Methods : The model contains seven job relating determinants and two intervening variables as follows: i) job relating variables of professional status, task requirements, pay, physician-nurse interaction, nurse-nurse interaction, organizational policies, and autonomy, ii) intervening variables of job satisfaction and organizational commitment. Data were collected from 205 nurses in two general hospitals owned by one foundation located in Pusan, Korea, using a structured and self-administered questionnaire. Results : The major results were as follows: First, the results of ANOVA on WPS by personal characteristics showed a statistically significant relationships between WPS and hierarchical orders(p<.01) ana tenure(p<.10). Comparing with the lower orders and shorter tenure, the higher orders and the longer tenure showed better WPS. Second, the results of simple correlation analysis between WPS and determinants and intervening variables showed the following variables, in order of importance, were statistically significant(p<.01): work satisfaction(+), organizational commitment(+), task requirements(+), nurse-interaction(+), professional status(+), physician-nurse interaction(+). Third, the results of path analysis showed that two intervening variables of job satisfaction and organizational commitment, and three determinants of task requirements, professional status, and nurse-nurse interaction had a positively significant direct effect to WPS. Conclusion : The results suggest that nurses who are more satisfied with task requirements, status, nurse-nurse interaction, overall job satisfaction, and organizational commitment, will behave in ways that patients find more satisfied.

• Earthquakes and Structures
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• v.18 no.1
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• pp.73-82
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• 2020

With the coal mining depth increasing, both stress and gas pressure rapidly enhance, causing coal and gas outburst risk to become more complex and severe. The conventional method for prediction of coal and gas outburst adopts one prediction index and corresponding critical value to forecast and cannot reflect all the factors impacting coal and gas outburst, thus it is characteristic of false and missing forecasts and poor accuracy. For the reason, based on analyses of both the prediction indicators and the factors impacting coal and gas outburst at the test site, this work carefully selected 6 prediction indicators such as the index of gas desorption from drill cuttings Δh₂, the amount of drill cuttings S, gas content W, the gas initial diffusion velocity index ΔP, the intensity of electromagnetic radiation E and its number of pulse N, constructed the Bayes discriminant analysis (BDA) index system, studied the BDA-based multi-index comprehensive model for forecast of coal and gas outburst risk, and used the established discriminant model to conduct coal and gas outburst prediction. Results showed that the BDA - based multi-index comprehensive model for prediction of coal and gas outburst has an 100% of prediction accuracy, without wrong and omitted predictions, can also accurately forecast the outburst risk even for the low indicators outburst. The prediction method set up by this study has a broad application prospect in the prediction of coal and gas outburst risk.