• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.31-38
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• 2014

Rooting agents and shading treatments were tested in two different experiments to determine their effects on the establishment success of hardwood cuttings of three highbush blueberry varieties 'Bluecrop', 'Duke' and 'Sunrise'. For the experiment with rooting agents, one-cm long bases of the cuttings were dipped into solutions of IBA or NAA for 5 s, both at 0, 500 and $1000mg{\cdot}L^{-1}$ in 50% ethanol, and were also treated with Rootone$^{(R)}$ powder. Determined 90 days after cutting, the percent rooting and root weight were increased by NAA at $500mg{\cdot}L^{-1}$ in 'Bluecrop' and 'Sunrise', while in 'Duke' IBA at $500mg{\cdot}L^{-1}$ was effective. These auxin treatments were found to work better than a commercial product Rootone$^{(R)}$. The rooting agent-induced increases in root development resulted in better shoot growth of the cuttings in all three varieties, as determined after 90 days of further growth in individual containers. In the experiment with shading treatments, different levels of the shading treatment (30 to 90%) were imposed over the cutting bed under no mist. In all three varieties, 30% shading increased the percent rooting and root and shoot growth, compared to no shading control. However, shading levels higher than 50% shading were found to be inhibitory for hardwood cuttings of highbush blueberries, especially under the environmental conditions with no mist system.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.121-125
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• 2009

There have been many developed systems for harnessing the solar energy such as solar water heaters, solar thermal power systems, PV systems, daylighting and solar hydrogen systems. all of them are capable of reducing $CO_2$ emission. However, the efficiency of those systems which work without a solar tracker is lower. This paper is a step by step procedure for fabrication and a performance test of a solar tracking system. The system developed in this study consists of motion controllers, motor drives, step-motors, feedback devices and application. CdS sensors are introduced into the solar tracking system for playing a primary role in poor conditions for tracking due to a gear backlash and a strong wind. Mini-dish was used as a concentrator for collecting sun light. The solar position data, in terms of azimuth and elevation, sunrise and sunset times was compared with those of KASI(Korea Astronomy & Space Science Institute). The results presented in this article provide the high accuracy of the present system in solar tracking and indicate a potential for energy savings.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.1
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• pp.40-46
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• 2010

In urban area, inversion layer prevents air pollutants from being dispersed. To determine nocturnal inversion characteristics at SookMyung Girls' High School near high-rise residential commercial complex buildings in Seoul, air temperature and humidity data were observed at 10minute interval from December 1st, 2007 to May 2nd, 2008. Temperature-Humidity (T-H) sensors were installed at SMG (SookMyung_Ground) and SMR (SookMyung_Roof), and then these two data were compared, analyzed and examined to illustrate air temperature differences of SMG and SMR. After the analysis, the maximum nocturnal inversion was observed by $3.3^{\circ}C$ at 18:10 on December 26th 2007, at that time the weather condition was clear and weak wind. Nocturnal inversions began 2-3 hours before sunset and it reached maximum inversion just after sunset and continued through nighttime until sunrise or 1-2 hours after sunrise. In terms of seasonal variation nocturnal inversions occurred dominantly in March and April rather than winter season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.48-54
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• 2017

The ecological characteristics of Pseudoblennius cottoides were investigated off Dolsan Island, Yeosu, Korea, from June to December, 2001. Their habitats were the reef zone and surrounding embankment which was covered with seaweeds. Their range of total length (TL) was 6.10-8.40 cm (n=15), and the individuals (over 8.10 cm) of them accounted for in June. It was 8.60-15.7 cm (n=67), and the individuals 11.1-12.0 cm in TL accounted for in October, 2001. The female to male sex ratio was 1:0.48 (n=185). The gonads were in the shape of a rod and the ovaries were large in size. In June, the histology of the seminiferous tubules was observed. In August, the testicles appeared. In October, spermatocyte was observed in the testes, and ovaries were observed in relation to circumference popularity and oocyte.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.6
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• pp.46-56
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• 1998

This study was performed to investigate thermal performances of two different types of flat-plate solar collector systems; natural circulation system and forced circulation system. Conclusions obtained from this study are summarized as follows; 1) In the natural circulation system, the total heat amounts retrieved by starting recovery soon after sunrise were ranged from 10.28 to 17.20MJ/m$^2$, while the total heat amounts retrieved by starting recovery after sunset were ranged from 5.31 to 10.77MJ/m$^2$. 2) The collector efficiency in natural circulation system were ranged from 51.1% to 54.1% when the collected heat was retrieved after sunrise and were 65.8~78.0% when the collected heat was retrieved soon after sunset. 3) According to the regression analysis between fluid flow rates and fluid temperature difference at inlet and outlet of collector pipe, there was high regressive corelations with regression coefficient, r, of 0.982. 4) The collector efficiencies estimated for forced circulation system were 73.1~88.6%, and 78.4~94.8%, and 64.2%~74.5%, respectively when fluid circulation rates were 4.2 l/min, and 7.0 l/min, respectively.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.127.1-127.1
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• 2012

The 40.8-MHz VHF coherent scatter ionospheric radar, located in South Korea (Gyeryong, $36.18^{\circ}N$, $127.14^{\circ}E$), has been operating since December 2009 to investigate ionosphere E- and F-region field-aligned irregularities (FAIs) of mid-latitude. During the observation, we found E- and F-region FAIs appeared frequently: continuous echoes during the post-sunrise period and Quasi-Periodic (QP) echoes at nighttime for E region ; strong post-sunset and pre-sunrise FAIs for F region. The characteristics of E- and F-region FAIs are presented in terms of seasonal and local time variations of occurrence during December 2009 to August 2012. In addition, to investigate the correlation with geomagnetic activity to FAIs occurrence, we compared K-index variations to local time occurrence. It is worth to note our occurrence result since long term observation over several years in the mid-latitude has not yet been carried out.

• Korean Journal of Remote Sensing
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• v.34 no.5
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• pp.749-762
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• 2018

In this study, the changes of the sunshine environment due to the construction of buildings were analyzed by season. Using a geographic information system (GIS) data, the topography and the buildings were constructed around Pukyong National University (PKNU) in Busan. The numerical model was performed for a week in each season, before and after the construction of buildings. Even before the construction of the high-rise building complex, the area of sunshine block is wide due to the apartment complex located in the southeast of the PKNU campus and the mountain in the south. After the construction, the sunshine-blocked area became wider after the sunrise and before the sunset. The area of sunshine block after 1 hour at sunrise increased by 1.60%, 1.50%, 1.58% and 1.36% in the vernal equinox, summer solstice, autumnal equinox and winter solstice, respectively. The building complex in the east (south) of the PKNU campus made shadow in more than 1,000 m (750 m) toward the west (east) just before the sunrise (sunset). Especially, the sunshine duration in PKNU campus decreased by 46.61%, 22.75%, 58.56%, and 11.31% in the vernal equinox, summer solstice, autumnal equinox and winter solstice, respectively. The analysis of the sunshine duration for a dormitory building showed that the construction of the building complex in the south of the PKNU campus reduced the sunshine area of the western (southern) wall of the dormitory by 30.91% (49.45%) for a winter week.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.161-172
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• 1969

Ten experimental tuna long line fishing operations were performed with the long lines A and B, in combination casting orders of BA and AB. The long line B differs from A in its additional main line length per basket and its greater depth of submersion (Table 1). The BA casting order results in an AB hauling order, so that the long line B is casted at an earlier time of a day and fishes for a longer period than A line (fig. 2). The number of fish caught was divided into subclasses in order to be subjected to $x^2-tests$ (Table 2). The first series of $x^2-tests$ were calculated using the hooking rates of two subclasses with other factors pooled (Table 3). The second series of $x^2-tests$ were calculated to obtain the interactions between two subclasses when other factors differed (Table 4). Attention was paid to the extremely small interactions as well as to the large interactions in order to find out whether a factor functions in the same way or in a contradictory way when the other factors involved differ. The test result is summarized in Table 5. The relationship between the hook casting time (relative to the sunrise time) and the hooking rates reveals the feeding behavior of particular species (fig. 3) A high hooking rate for yellowfin tuna shown in the period from one hour before sunrise to the moment of sunrise suggests that they feed actively in that period. Their poor hooking rate on earlier casted hooks suggests that they do not feed well under conditions of darkness and that they feed best while the hooks are sinking. Furthermore it is likely that yellowfin tuna maintain a shallow depth in the daytime, for the $x^2$ interaction between the line casting order BA and AB shows their persistant preferance of the long line A regardless of line casting order. Bigeye tuna show their feeding behavior under conditions of darkness, and show a preference for the sea's deeper layer. Alepisaurus borealis (Gill) show their feeding behavior under conditions of darkness more significantly than the bigeye tuna and their preferance for deep layers is also more significant. Marlins (mainly Makaria mazara) show a feeding behavior which is similar to the yellowfin tuna. The author emphasizes that certain variations of the hooking rates in relation to the line easting time were caused by an inadequate fishing depth as well as by the fish preference for a particular feeding time. When the part of the line casted in pre-dawn hours and hauled in the pre-sunset hours show a significantly lower hooking rate than other parts of the line, then it is concluded that tile hooks settled in a sea layer too deep for feeding.

• Publications of The Korean Astronomical Society
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• v.23 no.2
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• pp.53-63
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• 2008

Korea Astronomy and Space Science Institute (KASI), direct decendant of Korea National Astronomy Observatory, has been publishing Korean Astronomical Almanac since in 1976. The almanac contains essential data in our daily lives such as the times of sunrise, sunset, moonrise, and moonset, conversion tables between luni-solar and solar calendars, and so forth. So, we are planning to register Korean astronomical almanac data for national Standard Reference Data(SRD), which is a scientific/technical data whose the reliablity and the accuracy are authorized by scientific analysis and evalution. To be certificated as national SRD, reference data has to satisfy several criteria such as traceability, consistency, uncertainty, and so on. Based on similarity among calculation processes, we classified astronomical almanac data into three groups: Class I, II, and III. We are planning to register them for national SRD in consecutive order. In this study, we analyzed Class I data which is aimed to register in 2009, and presented the results. Firstly, we found that the traceability and the consistency can be ensured by the usage of NASA/JPL DE405 ephemeris and by the comparsion with international data, respectively. To evaluate uncertainty in Class I data, we solved the mathematical model and determined the factors influencing the calculations. As a result, we found that the atmospheric refraction is the main factor and leads to a variation of ${\pm}16$ seconds in the times of sunrise and sunset. We also briefly review the histories of astronomical almanac data and of standard reference data in Korea.

• Journal of the Korean Solar Energy Society
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• v.30 no.3
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• pp.98-107
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• 2010

This paper introduces step by step procedures for the design, fabrication and operation of a solar tracking system. The system presented in this study consists of motion controllers, motor drives, step-motors, feedback devices and other accessories to support its functional stability. CdS sensors are used to constantly generate feedback signals to the controller, which assures a high-precision solar tracking even under adverse conditions. It enables instant correction if the system goes off track by strong winds causing gear backlash. A parabolic dish concentrator is mounted on the tracking system whose diameter was 30cm. The solar position data, in terms of azimuth and elevation, sunrise and sunset times were compared with those of the Astronomical Applications Department of the U.S. Naval Observatory. The results presented here clearly demonstrate the high-accuracy of the present system in solar tracking, which are applicable to many existing solar systems.