• Nuclear Engineering and Technology
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• v.49 no.5
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• pp.989-995
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• 2017

Distributed Control System (DCS) communication networks, which use Fast Ethernet with redundant networks for the transmission of information, have been installed in digitalized nuclear power plants. Normally, failover tests are performed to verify the reliability of redundant networks during design and manufacturing phases; however, systematic integrity tests of DCS networks cannot be fully performed during these phases because all relevant equipment is not installed completely during these two phases. In additions, practical verification tests are insufficient, and there is a need to test the actual failover function of DCS redundant networks in the target environment. The purpose of this study is to verify that the failover functions works correctly in certain abnormal conditions during installation and commissioning phase and identify the influence of network failover on the entire DCS. To quantify the effects of network failover in the DCS, the packets (Protocol Data Units) must be collected and resource usage of the system has to be monitored and analyzed. This study introduces the use of a new methodology for verification of DCS network failover during the installation and commissioning phases. This study is expected to provide insight into verification methodology and the failover effects from DCS redundant networks. It also provides test results of network performance from DCS network failover in digitalized domestic nuclear power plants (NPPs).

• Economic and Environmental Geology
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• v.41 no.2
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• pp.183-199
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• 2008

This study is focused on characterization of the physio-chemical and mineralogical properties, investigation of their vertical changes in the tailing profile of the Guryoung mining area, classification of the profile into distinct zones, and condition conceptual model of physio-chemical conditions and phases-water relationships controlling the element behaviors in the tailings. The upper part of the groundwater is characterized by the high contents of $Fe_2O_3$ and $SO_3$ for whole rock analysis, low pH, and the occurrence of jarosite, schwertmannite and Fe-oxyhydroxide as the secondary mineral phases. The tailing profile can be divided into the covering soil, jarosite zone, Fe-sulfate zone, Fe-oxyhydroxide and gypsum-bearing pyrite zone, calcite-bearing pyrite zone, soil zone, and weathered zone on the based of the geochemical and mineralogical characteristics. The profile can be sampled into the oxidized zone and the carbonate-rich primary zone with the dramatic changes in pH and the secondary mineral phases. The conceptual model proposed for the tailing profile can be summarized that the oxidation of pyrite is the most important reaction controlling the changes in pH, the dissolution of the primary silicates and carbonates, the precipitation of secondary mineral phases, acid-neutralizing, and heavy metal behaviors through the profile.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.1
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• pp.32-37
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• 2018

The aim of this study is to investigate influence of moon light to the fishing of squid jigging fishery in the southwest Atlantic Ocean based on analyses of date taken from 127 vessels in Falkland fishing ground by squid jigging fishery from 2010 to 2015. Catch and CPUE were analyzed between the new moon and full moon phases. Catches of the new moon phase were higher than those of the full moon phase by 7.6% and CPUE expressed in mt/day-vessels and mt/line-day were also higher by 18.2%, 18.2% respectively. However, as a result of statistical analysis at a significance level of p > 0.05, no significant statistical differences in catch, mt/day-vessels and mt/line-day were found between the new moon and the full moon as a result of statistical analysis at a significance level of p > 0.05.

• 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.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.03a
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• pp.1-11
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• 2004

Ion-exchange membranes have been widely used in various applications such as diffusion dialysis, electrolysis, electrodialysis, fuel cell etc [1-2]. When an electric current passes through the membrane system, the current is carried by both positive and negative ions in the bulk solution phases, whereas it is carried mainly by the counter-ions in the membrane. (omitted)

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.118-119
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• 2006

• Journal of Korean Society for Quality Management
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• v.22 no.2
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• pp.33-40
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• 1994

Most software reliability models and other methods attempt to estimate some measures based on its fault history. There are several phases of the software life cycle including testing phase. We can propose it's stopping rule to decide when to stop the testing and pass it on to the next phase by considering the detailed structure of software and calculating the failure rate when each fault was detected. Downs (1985) proposed a method which was developed for estimating the failure rate applicable only to two-level profiles. In this paper, I extended to profiles involving more levels.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.447-454
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• 1996

Clay mineral geothermometry using sericites and chlorites in Bobae sericite mine reveals that these clay minerals formed at relatively high temperature. It appears that sericites formed at around $200{\sim}350^{\circ}C$ and chlorites formed at around $250^{\circ}C$. X-ray diffraction study of these minerals reveals that sericite 2M, type and chlorite lib type are dominant phases. Both polytypes indicate that the precipitation temperatures of these minerals shows fairly good agreement with the estimated temperature by clay mineral geothermometry. The Bobae sericite mine was formed at relatively higher temperature than several non-metal ore deposits occurred in the southern part of Korea.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.177-180
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• 1997

A new excitation method of switched reluctance moor drive is described in this paper. This motor produces reluctance torque by mutual action between tyro phases as well as conventional self reluctance torque. The change of self inductance and mutual inductance are used to produce torque. This paper suggests the operational principle, the mechanism of torque product and the driving characteristics of Switched Reluctance Motor with 2 phase excitation against conventional SRM experimentally. The energy conversion ratio is increased because the next phase is excited after one phase is already excited. Acoustic noise of SRM with 2 phase excitation is decreased than that of conventional SRM due to the mechanism of torque production.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.4
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• pp.349-356
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• 2017

The catch composition of commercially important species of the stationary lift net at Barangay Gines, Miagao, Iloilo, the Philippines was investigated from December 2013 to May 2014 during the different phases of the moon. A total of 486 kg of fish coming from 12 different genera, including mollusk and crustaceans, was caught and identified from the catch of the stationary lift net. Among the 12 genera identified from the catch of stationary lift net, anchovy (Stolephorus), sardines (Sardinella), squid (Loligo) and mysid shrimp (Acetes) were considered to be commercially important due to their value. Acetes catch was highest during the new moon in the month of January. Loligo catch was also high during the new moon except in the month of May. Stolephorus catch was also highest during the new moon except in the month of January. Sardinella catch was highest during the first quarter in the month of February. Full moon had the lowest catch all throughout the duration of the study while new moon had the highest catch during December 2013 to March 2014 and first quarter was the highest in the months of April and May.