• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.394-397
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• 2004

Working-day calculation with weather factors of construction-site has estimated wethout proper data. They usually estimate it with their own experience and intuition. It causes not only economic loss to time-adjustment but also conflict with each participants. Moreover, weather estimation becomes worse than before, due to tendency of recently weather change. So, in this paper we present optimal estimation method as assessment by period of the arithmetical mean methods. For that, we analyse characteristic of the regions and weather change of temperature and rainfall which affects time.

• Tribology and Lubricants
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• v.26 no.6
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• pp.329-335
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• 2010

Recently, the End-milling processing is needed the high-precise technique to get a good surface roughness and rapid time in manufacturing of precision machine parts and electronic parts. The optimum surface roughness has an effect on end-milling working condition such as, cutting direction, spindle speed, feed rate and depth of cut, and so on. It needs to form the correlation of working conditions and surface roughness. Therefore this study was carried out to presume of surface roughness on end-milling working condition of Al7075 by regression analysis. The results was shown that the coefficient of determination($R^2$) of regression equation had a fine reliability of 87.5% and nonlinear regression equation of surface rough was made by multiple regression analysis.

• Korean Institute of Interior Design Journal
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• no.30
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• pp.42-50
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• 2002

This research deals with a new concept regarding creative enlargement in order for useful space composition. Architecture, through interior design case analysis has given birth to a new concept and inspiration altering interior designer's perspectives on the future environment. Focusing exclusively on those offices that express in design terms a commitment to such concepts as team-Working, just-in-time Working, virtual and mobile working and those using the newest technological tools and the latest space-planning concepts available. Emphasis is placed on how an office environment can be designed to encourage group working, the sharing of knowledge, a spirit of community within larger organizations, and non-territorial working-employees that work where and how they want supported by cordless technologies.

• Journal of Chest Surgery
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• v.25 no.2
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• pp.131-136
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• 1992

The effect of temperature of cardioplegic solution on myocardial preservation was studied using isolated rat heart perfusion technique. Twenty Sprague-Dawley rats, weighing 120~140gm, were pretreated with intraperitoneal injection of heparin sodium[300u/kg] and then the hearts were excised after cervical herniation 30 minutes later. The hearts were perfused in isolated working heart apparatus with oxygenated modified Tyrode solution at 37oC. After 10 minutes of non working heart perfusion, the hearts were subjected to arrest for 30 minutes by administration of 5cc cardioplegic solution at the temperature of 4oC [Group I ], 15oC [Group II], 25oC [Group III], 37oC[Group IV]. At the same time, the topical cooling of heart was performed using ice saline. After arrest, the hearts were reperfused by non working heart perfusion for 1 hour with modified Tyrode solution at 37oC. The CPK, GOT and LDH in reperfusate were measured at 5,20,40,60 minutes after start of reperfusion. With the values of those, we compared the effect of temperature of cardioplegic solution on myocardial preservation. The results were as follows; 1. The enzyme values in reperfusate were highest at 5 minute and after then declined. 2. At 5 minutes after reperfusion, the enzyme values in Group I were lower than those in other Groups. These results suggest that the cardioplegic solutions using for cardiac arrest and myocardial protection can be working better at 4oC than at any other temperature.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.6
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• pp.74-80
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• 2022

The surface status of a workpiece determines its functionality, product quality, and manufacturing costs. Thus, several finishing technologies have been widely investigated and applied to improve surface characteristics. In this study, rotational electro-magnetic abrasive finishing (REMAF) was suggested as a non-contact finishing process to achieve high geometric precision. To verify the effects of the REMAF process on burr removal on the surface of Al6061, experiments were conducted using the Taguchi method. Based on the experimental results analyzed by the S/N ratio and ANOVA, the optimal conditions were defined as A₃B₂C₃D₃ that corresponded to 1,800 rpm of rotational speed, 1.5 kg of abrasive particle weight, 0.7 mm of abrasive diameter, and 15 min of working time. In addition, the particle weight was a key attribute for deburring, whereas the working time was less effective.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.28.1-28.12
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• 2023

Background: Owing to the coronavirus disease 2019 pandemic, being exposed to work from home and work during nonwork time simultaneously can lead to sleep disturbance; however, their combined effect is unclear. We aimed to investigate the combined effect of work from home and work during nonwork time on sleep disturbance. Methods: This study used data from the Sixth Korean Working Condition Survey and included 27,473 paid workers. Logistic regression analysis was conducted to investigate the relationship between work from home, work during nonwork time, and sleep disturbance according to sex. We re-classified participants into 4 groups based on their working from home (No/Yes) and working during nonwork time (No/Yes). The relative excess risk due to interaction was calculated to examine the effect of exposure to both telecommuting and non-regular work hours on sleep disturbance. Results: Workers exposed to work from home and work during nonwork time had significantly higher risks of sleep disturbance for all, men, and women workers (OR [95% CI]: 1.71 [1.46-2.02], 1.79 [1.43-2.23], and 1.64 [1.29-2.08] for work from home and 3.04 [2.70-3.42], 3.61 [3.09-4.22], and 2.41 [2.01-2.90] for work during nonwork time, respectively). Compared to those who were not exposed to both factors, when workers had both job factors, the ORs (95% CI) of sleep disturbance for all, men, and women were 3.93 (2.80-5.53), 5.08 (3.21-8.03), and 2.91 (1.74-4.87), respectively. The relative excess risk due to interaction of work from home and work during nonwork time was not significant for sleep disturbance. Conclusions: Work from home and work during nonwork time were each associated with sleep disturbance, but the interaction between the two factors on sleep disturbance was not observed in both men and women.

• Journal of Information Technology Applications and Management
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• v.20 no.4
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• pp.249-261
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• 2013

Through smart work using by smart technologies, many organizations wish to change traditional working styles. Lots of organizations, however, wish to do work with smartness through adoption of smart work technologies, those are not sure whether smart work will be successful or not till now. Viewpoints of members concerning efficiency and effectiveness from smart work who operate the organizations may be different. Therefore, hopefully, this research tried to investigate whether differences among members of organizations by empirical and exploratory approach. Totally, 118 questionnaires had been collected and performed test of mean difference between groups. As a result, some items such as working place, working methods, flexible time and tension of smartwork showed significant differences among groups and non-leader and leader groups. And, furthermore, from this research I believe that we can have a few insights for successful smart working environment in organizations. For successful smart work, organizations have to try to overcome or minimize differences among members of organization.

• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.543-551
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• 2012

Objectives : School-age children have mixed dentition and are sensitive to dental caries. Their dental condition is more important as it is directly related with oral health in their life, and parents' attention and education are necessary as the children can not manage their oral health voluntarily. Methods : To evaluate the effect of parents' occupational status on the oral health of children, this study conducted a questionnaire survey and analyzed the results along with the results of oral examination with 952 students and their parents of an elementary school located in Ulsan conducting school oral health projects on May, 2009. Results : As dental caries prevalence rate recorded 33.7%, 56.8% and 66.9% in non-dual income, professional dual income and non-professional dual income families, respectively, the rate of children of dual income families was significantly higher than that of non-dual income ones (p<0.05). Conclusions : For professional dual income families, although working mothers contribute to economic stability, they took less time to care or to educate their children compared to no-working mothers so that they need to pay more attention to oral health of children. In addition, more interest to and education for children of non-professional dual income families showing relatively lower socio-economic level and lack of time for children, were also necessary in school projects on oral health education and prevention.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.61-69
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• 2018

Construction projects consist of long-term on-site production, and most disciplines are featured by outdoor works. Therefore, when a process plan is established, non-working days are calculated and reflected in a process schedule to comply with the planned construction period. However, necessary information and working methods are different in the course of the work, so the method of calculation varies depending on persons even for the same site, and the result is also very different. Therefore, scientific and quantitative understanding of business information is needed. This study reconstructed non-working day estimation process by collecting and organizing the information necessary for non-working day estimation, and designed the demonstration screen based on the reconstructed process and verified through expert interview at each stage. As a result, it showed about 69% reduction of work time and reliability of 92% work information matrix, and 80% of the experts evaluated the systemization of the relevant work. This study is expected to improve the understanding of work and increase the efficiency of work performance, and the study on systemization in the future should be continued.

• Wind and Structures
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• v.38 no.2
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• pp.129-146
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• 2024

Aiming at the problem of non-stationary wind field simulation of downbursts, a non-stationary down-burst generation system was designed by adding a nozzle and program control valve to the inlet of the original wall jet model. The computational fluid dynamics (CFD) method was used to simulate the downburst. Firstly, the two-dimensional (2D) model was used to study the outflow situation, and the database of working conditions was formed. Then the combined superposition of working conditions was carried out to simulate the full-scale measured downburst. The three-dimensional (3D) large eddy simulation (LES) was used for further verification based on this superposition condition. Finally, the wind tunnel test is used to further verify. The results show that after the valve is opened, the wind ve-locity at low altitude increases rapidly, then stays stable, and the wind velocity at each point fluctuates. The velocity of the 2D model matches the wind velocity trend of the measured downburst well. The 3D model matches the measured downburst flow in terms of wind velocity and pulsation characteris-tics. The time-varying mean wind velocity of the wind tunnel test is in better agreement with the meas-ured time-varying mean wind velocity of the downburst. The power spectrum of fluctuating wind ve-locity at different vertical heights for the test condition also agrees well with the von Karman spectrum, and conforms to the "-5/3" law. The vertical profile of the maximum time-varying average wind veloci-ty obtained from the test shows the basic characteristics of the typical wind profile of the downburst. The effectiveness of the downburst generation system is verified.