• Journal of Urban Science
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• v.8 no.2
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• pp.29-34
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• 2019

Benzene pollution is becoming increasingly serious, and the treatment technology of benzene has attracted much attention. In this paper, a self-made photocatalytic reactor was used to explore the removal rate of benzene under the ultraviolet light with the wavelength of 253.7nm. The results showed that the degradation rate of benzene decreased from 64.29% to 16.26% when the concentration increased from 43mg/㎥ to 256mg/㎥ under the condition of 28W UV light intensity and 50s residence time. Under the condition of 28W UV light intensity and 103mg/㎥ concentration, the residence time increased from 16.5s to 50s, and the benzene removal rate increased from 13.23% to 42.72%.Under the condition of benzene concentration 103mg/㎥ and residence time of 50s, the removal rate of benzene increased from 29.34% to 52.58% in the process of UV light intensity rising from 28W to 48W.It is concluded that decreasing the concentration and increasing the residence time of gas were beneficial to the removal of benzene and increasing the light intensity can improve the removal rate of benzene.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1359-1361
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• 1996

This paper describes a design of real time fuzzy controller using Minimum fuzzy control Rule Selection Method(MRSM). The control algorithm of dynamic systems needs less computation time and memory. To reduce the computation time of fuzzy logic controller, minimum number of rules are to be selected for the fuzzy input variable. The universe of discourse is divided by the number of linguistic labels to allocate the assigned membership function to the fuzzy input variables. In this case, since fuzzy input variables are continuous, scale factor SU is tuned independently. According to increment of SU control surface is improved to adapt the change of system parameter. At this, crisp control surface is increased. With the increament of crisp control surface, fuzzy control surface is reduced. When error state deviates from desirable error state, crisp control surface is more useful than fuzzy control surface for obtaining fast rising time.

• Journal of Families and Better Life
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• v.34 no.3
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• pp.65-84
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• 2016

This study examined the factors that were associated with longitudinal changes for ten years from 2004 to 2014 in time spent on housework by married couples who had a preschooler as their first-born child. It also sought to figure out how much of such temporal changes were attributable to differences in the means on associated factors as well as to differences in the influence or slope of such factors. A total of 9,668 time diaries from the Korean Time Use Survey were used to analyze the influence of couple's weekly work hours, wife's relative income, couple's education and gender role attitudes on the time spent on housework of husbands and wives. Results from descriptive statistics, regression and decomposition analysis were as follows. First, women decreased, while men increased their time doing housework. Second, weekly work hours of husband and wife were related to their time doing housework in every year surveyed. Third, wife's relative earnings and couple's gender role attitudes affected wife's time doing housework more than husbands', whereas couple's education had stronger effects on husbands than wives. However, such influence was apparent on a certain survey year, and then disappeared in another, or became stronger or weaker longitudinally. Fourth, the temporal decrease in wife's housework time and increase in husband's housework time were attributable to social and cultural changes such as reduced working hours, rising female income, higher educational background, and prevalence of egalitarian gender role attitudes. Findings suggest that the trend in spending time on housework is expected to continue, and provide a timely policy implications to facilitate the change.

• Journal of The Korean Astronomical Society
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• v.50 no.6
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• pp.191-200
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• 2017

We analyze the time data recorded in Korean astronomical almanacs for the years from 1913 to 1945, which belong to the period in which Japan occupied Korea (1910-1945). These almanacs, published by Japanese scholars, differ from previous almanacs in terms of organization, content, and calendrical methods. In this study, we first extract twelve kinds of time data from the almanacs at the following times: solar terms, rising and setting of the Sun and Moon, transit of the Sun, phases of the Moon (i.e., new Moon, first quarter Moon, full Moon, and last quarter Moon), and eclipses of the Sun and Moon. Then, we compare the time data with that obtained from modern calculations. Even though all time data in the almanacs are tabulated in units of minutes, we calculate the data in units of seconds and determine the root mean square (RMS) deviation values for each kind of time data to estimate the accuracy of the data. Our findings are as follows: First, the kind and tabulation method of time data changes several times. For instance, solar transit time is listed only for six years from 1937 to 1942. Second, the times of two equinoxes and those of a new Moon are considerably close to midnight. Third, there are some typographical errors in the almanacs, particularly in the times of moonrise and moonset. Fourth, the contact times for lunar eclipses represent the times of the umbra and not of the penumbra, which is different from the times for solar eclipses. Finally, the RMS deviation values are approximately 0.5 min on average in all kinds of time data, even though they show slightly large differences in the times related to the Moon. In conclusion, we believe that this study is useful for investigating the time data in the almanacs of other East Asian countries that were published during the same period, such as China, Japan, and Manchuria.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.2
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• pp.63-70
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• 1999

This paper is proposed a new method to deal with the optimized auto-tuning for the Pill controller which is used to the process-control in various fields. First of all, in this method, 1st order delay system with dead time which is modelled from the unit step response of the system is Pade-approximated, then initial values are determined by the Ziegler-Nichols method. So we can find the parameters of Pill controller so as to minimize the fuzzy criterion function which includes the maximum overshoot, damping ratio, rising time and settling time. Finally, after studying the parameters of Pill controller by Backpropagation of Neural-Network, when we give new K, L, T values to Neural-Network, the optimized parameter of Pill controller is found by Neural-Network Program.rogram.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.128-131
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• 2004

This paper is to investigate the mock up test results of mass concrete for transfer girder using setting time difference with super retarding agent(SRA) to reduce hydration heat. According to test results, the temperature history of plain concrete without placing lift had a steep rising curvature, and plain concrete had a big temperature difference between surface and middle section of mass concrete, which may result in occurrence of temperature crack. However, considering placing method B, because setting time of middle section concrete was retarded with an increase in SRA contents, higher hydration heat temperature was observed at surface section concrete compared with that at middle section concrete at early age, which can lower the possibility of hydration heat crack. In case of placing method C, although peak temperature of hydration heat was much lower, at early age, high crack occurrence possibility of the hydration heat attributable to the big temperature difference between middle section and bottom section of concrete was expected at bottom section concrete. Therefore, the structure above the ground like transfer girder is not applicable to consider the placing method C.

• Archives of design research
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• v.15 no.4
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• pp.285-294
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• 2002

According to the dramatical changes from individual trip to the family and couple trip in 1990 caused by both economic growth, rising the level of people's income, and change of social structure such as the increasing time due to the fact of automatic system, and social trends to use this time for their leisure time, this trend influences on the cruise. recently, required for accommodating room to family, the cruise decorated with luxurious things becomes the center of public attention. This study should be a foundation works for developing domestic cruise in near future through surveying a floor plan (plan of room and deck), picture of room, characteristic of space, finish material and interior spatial organization factor & characteristic and analyzing them.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.717-722
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• 2013

The wastewater reclamation and reusing system has been rising as an alternative of water resource exhaustion that the whole world is experiencing. In order to be able to bring about improvement of the existing wastewater reclamation and reusing system, this research has developed of Conversion-Human Machine Interaction (C-HMI) based real-time control and monitoring system such as a sensor module and gate module, web monitoring system. This system was communication almost-error-free in various environment and situation. As a result, we have achieved our goal that has to doing work correctly as a sensor and gateway module that communication error is less than 0.2% throughout the embodied system and add that it can be easily controled and configured as an interface equipment to a complex sensor of water quality. According to this, the construction of a database capable of analyzing and assessing collection, storage and various elements of reliable water quality and flow rate data can be possible.

• Journal of Advanced Navigation Technology
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• v.12 no.2
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• pp.109-114
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• 2008

As the Ubiquitous times approach, an interest regarding a Ubiquitous sensor network to be the only during key technology is rising. Currently, The fast development which radio communication technique is creating new services from the industry sector which is various from convenient characteristic and the ease characteristic side. Specially, rise and development of the radio communication technique which is various from environment monitor ring field makes to be improved about sharp curtailment of establishment and logistics relation expense, and collection period of the data which occurs real-time from site, reliability and delivery characteristic. But continuous application and the success about the environment monitor ring field of radio communication technique will be able to trust And It is important to provide time information which is appropriate real-time.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.3
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• pp.373-378
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• 2008

The pH & alkalinity adjustment method by lime and carbon dioxide($CO_2$) for corrosion control in water distribution system was investigated to determine the optimum operational condition in lime adding process in water treatment plant(WTP). The mixing time at dissolution tank and sedimentation time at saturator for maintaining optimal turbidity condition of lime supernatant were 60~75 minutes and 75~95 minutes, respectively. There was no difference according to $CO_2$ adding methods such as $CO_2$ saturated water or $CO_2$ gas. But, $CO_2$ saturated water could be convenience at WTP in terms of pH control and quantitative dosing. To minimize generation of calcium carbonate products, the short time interval between adding of lime and $CO_2$ is most important. The lime should be added below 32 mg/l for preventing pH rising and generation of calcium carbonate products at the heating condition.