• 수산해양기술연구
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• 제58권4호
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• pp.317-325
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• 2022

Korean tuna purse seine fishery in the Western and Central Pacific Ocean (WCPO) began to operate in earnest in the early 1980s. Since then, the total catch has shown an increasing trend and the target species are skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacare) and bigeye tuna (Thunnus obesus). Based on the operational data of Korean tuna purse seine fishery from 2016 to 2020, the catch rates of target species (skipjack and yellowfin tunas) were analyzed by operation time for set types (free school and FAD sets). In the case of the free school sets, they were usually made from sunrise to sunset, and the catch rate was high before and after sunrise for skipjack tuna and before sunset for yellowfin tuna. On the other hand, for the FAD sets, more than 90% of them were made just before sunrise, and there were few operations during the daytime. The purpose of this study is to examine whether there are differences in the catch rate of skipjack and yellowfin tunas by operation time and by school type for Korean tuna purse seine fishery in the WCPO, which could be helpful in understanding its fishing characteristics and providing useful information for developing the stock indices of the target species.

• 한국환경생태학회지
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• 제28권4호
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• pp.411-418
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• 2014

본 연구는 빛공해 및 환경요인이 박새의 새벽 울음 시간에 미치는 영향을 밝히는데 목적이 있다. 연구대상지는 빛공해지역은 원주시 상지대학교 캠퍼스를 자연지역은 치악산국립공원 서측 산림으로 선정하였다. 녹음기간은 2014년 3월 26일에서 5월 30일이었다. 빛공해에 따른 새벽 울음 시작 시간을 분석한 결과 빛공해지역이 자연지역보다 먼저 울음을 시작하는 경향이 뚜렷하였다(p<0.05). 박새는 주로 일출 전에 첫 울음을 시작하였는데, 대부분의 조사일에서 상지대학교의 박새가 먼저 울기 시작하였다. 이로 인해 암컷이 미성숙한 수컷과 교미할 확률이 높아지고, 적정 번식기보다 일찍 새끼가 부화함으로 해서 먹이자원이 부족할 가능성이 높을 것으로 판단되었다. 환경요인에 의한 영향은 일출시간, 시민박명, 항해박명, 천문박명, 평균온도, 최고온도, 최저온도, 월출시간, 운량과 박새의 새벽 울음소리와의 상관관계를 분석하였다. 야생조류 울음 시작시간은 월출시간과 운량을 제외한 모든 환경요인의 상관관계가 인정되었다. 박새는 일출시작 이전에 날이 밝아지기 시작하는 시민박명 전후에 첫 울음을 시작하였고, 일출시간과 대기 온도가 상승함에 따라 새벽 울음 시작시간도 앞당겨졌다. 월출시간과 운량은 상관관계가 인정되지 않았는데 이에 대해서는 추가적인 연구가 필요하다.

• 원예과학기술지
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• 제29권4호
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• pp.317-325
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• 2011

본 연구는 보광이 착색단고추의 수량과 품질에 미치는 영향을 구명하여 생산성과 품질향상을 위한 착색단고추 재배기술 확립의 기초 자료를 얻고자 수행하였다. 보광시간대별 광합성은 아침 일출 전 보광에서는 1.5-$3.0{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$의 광합성속도를 나타냈으며, 일몰 후 보광은 0.5-$1.5{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$의 광합성속도를 보여 일출 전 보광이 더 효과적인 것으로 나타났다. 보광에 따른 증산율과 기공전도도는 일출 직후 보광과 함께 높게 상승한 후 소등 후 다시 감소하였다. 보광에 따른 기공면적은 $32.2{\mu}m^2$로 나타났으며, 자연일장(무처리)은 $7.7{\mu}m^2$로 현미경상에서 거의 닫힘 상태를 보였다. 보광에 따른 생육특성에서 스피리트 품종의 경우 초장은 일출 전 후 3시간 보광에 비하여 일몰 후 3시간 보광이 크게 나타났으며, 보광처리가 자연일장에 비하여 모두 초장이 높은 것으로 나타났다. 평균 착과수는 일출 전 후 3시간 보광이 4.3개였고, 일몰 후 3시간 보광은 3.7개였으며, 자연일장은 2.6개로 보광처리가 자연일장에 비하여 착과수가 많았다. 과실의 당도는 보광처리에 따른 유의적인 효과는 없었으나, 수확시기에 따라서는 약간 차이가 있었다. 10a당 상품수량은 스피리트 품종의 경우 보광 처리시 11,605kg인 반면, 자연일장은 7.578kg이었다. 전력소모와 시설비에도 불구하고, 경제성 분석결과 순소득도 일출 후 3시간 보광이 자연일장보다 51%정도 높게 나타났다.

• 대기
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• 제24권1호
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• pp.17-27
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• 2014

In this study, the observational environment for sunshine duration at Seoul and Daegu Automated Synoptic Observing Systems (ASOSs) was analyzed using a numerical model. In order to analyze the effects of topography and buildings on observational environment for sunshine duration, the model domains including the elevated building and mountainous areas around Seoul and Daegu ASOSs were considered. Three dimensional topography and buildings used as input data for the numerical model were constructed using a geographic information system (GIS) data. Solar azimuth and altitude angles calculated for the analysis period (one-week for each season in 2008) in this study were validated against those by Korea Astronomy and Space Science Institute (KASI). The starting and ending times of sunshine duration observed at ASOSs largely differed from the respective sunrise and sunset times simply calculated using solar angles and information of ASOSs' latitude and longitude, because uneven topography and elevated buildings around ASOSs cut off sunshine duration right after the sunrise and right before the sunset. The model produced the sunshine indices for Seoul and Daegu ASOSs with the time interval of one minute and the period of one week for each season and we compared the hourly averaged indices with those observed at the ASOSs. One week of which the cloudiness is lowest for each season is selected for analysis. Not only the adjacent buildings but also distant buildings and mountain cut off sunshine duration right after the sunrise and right before the sunset. The buildings and topography cutting off sunshine duration were found for each analyzing date. It was suggested that, in order to evaluate the observational environment for sunshine duration, we need to consider even the information of topography and/or building far away from ASOSs. This study also showed that the analyzing method considering the GIS data is very useful for evaluation of observational environment for sunshine duration.

• 대한원격탐사학회지
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• 제34권5호
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• pp.749-762
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• 2018

본 연구에서는 고층 건물 신축에 의한 주변 지역의 일조 환경 변화를 계절별로 분석하였다. 지리정보시스템(geographic information system, GIS) 자료를 이용하여 부산광역시 부경대학교 일대를 중심으로 지형과 건물을 구축하고, 고층 건물 건설 전과 후에 대해 계절별로 일조 모델을 수행하였다. 고층 건물 단지 건설 전에도 대상 지역의 남동쪽에 위치한 아파트 단지와 남쪽에 위치한 봉오리산의 영향을 받아 일조 차단 영역이 넓게 나타났다. 고층 건물 단지 건설에 의해 주변 지역의 일조 시간이 감소하였고, 일출과 일몰 시간대에는 일조 차단 면적이 증가하였다. 일출 1시간 후의 경우에는 춘분(1.60%), 추분(1.58%), 하지(1.50%), 동지(1.36%) 순으로 일조 차단 면적이 증가하였다. 부경대학교 동쪽(남쪽)에 건설된 고층 건물 단지는 일출(일몰)시 서쪽(동쪽)으로 1,000 m(750 m) 이상의 지점까지 일조가 차단되었다. 특히, 부경대학교 내부에서는 춘분, 하지, 추분, 동지에 각각 46.61%, 22.75%, 58.56%, 11.31%의 일조 시간이 감소하였다. 부경대학교 기숙사 건물에 대해 겨울철 1주일 동안 일조 시간을 조사한 결과, 남쪽 고층 건물 단지 건설은 기숙사 건물 서쪽(남쪽) 벽면의 일조 면적을 30.91%(49.45%) 정도 감소시켰다.

• Journal of Astronomy and Space Sciences
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• 제30권4호
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• pp.327-334
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• 2013

The purpose of this study is to develop an observation program for obtaining effective flat images that are necessary for photometric observation. The development of the program was achieved by improving the existing method for obtaining twilight flat images. The existing method for obtaining twilight flat images acquires flat images by observing the sky light after sunset or light before sunrise. The decision of when to observe flat images at each night is solely dependent on the judgment of an observer, and thus the obtained flat images for particular nights may not be clean. Especially, in the case of the observatories where an automated observation system is in operation, there is a difficulty that an observer should pay attention during sunrise and sunset in order to obtain flat images. In this study, a computer program is developed to improve this inconvenience and to efficiently perform photometric observation in the observatories where an automated observation system is applied. This program can obtain flat images by calculating the time for obtaining flat images automatically and the exposure time using a numerically calculated function. When obtaining twilight flat images at dusk and at dawn, the developed program performs automated observation and provides effective flat images by acquiring appropriate exposure time considering the sunrise and sunset times that vary depending on the day of observation. The code for performing this task was added to Obs Tool II (Yoon et al. 2006), which is the automated observation system of the Chungbuk National University Observatory, and the usefulness of the developed program was examined by performing an actual automated observation. If this program is applied to other observatories where automated observation is in operation, it is expected that stable and high-quality flat images could be obtained, which can be used for the pre-processing of photometric observation data.

• 한국환경복원기술학회지
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• 제13권1호
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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.

• 수산해양기술연구
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• 제52권2호
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• pp.96-102
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• 2016

In order to establish the basic data for the active use of the LED light source in the aquaculture industry, the experiment about the behavior of rockfish (Sebastes inermis) corresponding to the LED light was conducted by image analysis. LED lights for the experiment were one red light (wave length: 622 nm; light power: 811 mW) and two green lights (wave length: 518 nm; light power: 648 mW, wave length: 518 nm; light power: 810 mW). Behavior of the rockfish was analyzed using a moving distance (MD5) for 5 minutes where MD5s during the period of feeding were 20.0 m, 19.6 m, 16.3 m and 20.5 m in the ch1, ch2, ch3 and ch4. At the sunrise, mean MD5 of the entire channel about right before and right after were 6.3 m and 8.2 m. At the sunrise, mean MD5s of the entire channel about right before and right after were 13.6 m and 12.0 m. In the ch1, ch2 and ch3, mean MD5s during the period of 24 hours were 13.2 m, 9.6 m and 6.8 m at experiment 1and 5.2 m, 3.8 m and 2.9 m in the experiment 2.

• Journal of Astronomy and Space Sciences
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• 제28권3호
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• pp.173-181
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• 2011

Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Mt. Bohyun Observatory to measure the Earth's magnetic field variations in South Korea. We, in 2007, installed a fluxgate magnetometer (RFP-523C) to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we provide the preliminary and the first statistical analysis using the BOH magnetometer installed at Mt. Bohyun Observatory. By superposed analysis, we find that daily variations of H, D, and Z shows similar tendency, that is, about 30 minutes before the meridian (11:28) a minimum appears and the time after about 3 hours and 30 minutes (15:28) a maximum appears. Also, a quiet interval start time (19:06) is near the sunset time, and a quiet interval end time (06:40) is near the sunrise time. From the sunset to the sunrise, the value of H has a nearly constant interval, that is, the sun affects the changes in H values. Seasonal variations show similar dependences to the sun. Local time variations show that noon region has the biggest variations and midnight region has the smallest variations. We compare the correlations between geomagnetic variations and activity indices as we expect the geomagnetic variation would contain the effects of geomagnetic activity variations. As a result, the correlation coefficient between H and Dst is the highest (r = 0.947), and other AL, AE, AU index and showed a high correlation. Therefore, the effects of geomagnetic storms and geomagnetic substorms might contribute to the geomagnetic changes significantly.

• Korean Journal of Acupuncture
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• 제36권4호
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• pp.252-263
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• 2019

Objectives : This research aimed to 1) analyze the true meanings of the chapter, 'Wigi Haeng (Wei Qi Xing), the movement of guard qi' in Youngchu (Ling Shu) from the point of view of ancient Chinese Astronomy, 2) calculate the speed of Wigi over 24 Chinese seasons, 3) analyze the true meaning of daytime and nighttime in the chapter. Methods : 1) The chapter 'Wigi Haeng' was analyzed using concepts of ancient Chinese astronomy, 2) the records of angular distances of 28 constellations in the Book of Han (Han Shu) were used to analyze the meanings, and 3) the records of lengths of daytime and nighttime in the Book of Hou Han (Hou Han Shu) were used to calculate the speed of Wigi. Results : 1) The author of the chapter 'Wigi Haeng' did not consider the irregularity in the angular distances of the 28 Chinese constellations (Su). 2) The commentary in the Huangjenaegyong Taeso (Huang Di Nei Jing Tai Su) about the constellations in the chapter is correct. 3) The speed of Wigi changes in daytime and nighttime depending on the seasons. 4) When the speed of Wigi increases in daytime, the speed in nighttime decreases, and vice versa. 5) The beginning of daytime in 'Wigi Haeng' is not the time of sunrise but the time of dawn (2.5 Gak before sunrise). The nighttime ends 2.5 Gak after sunset. Conclusions : 1) The chapter 'Wigi Haeng' demonstrates the ancient astronomical point of view on the universe and the movement of Wigi. The speed of Wigi is variable. 2) This chapter does not address the irregularity in the angular distances of the 28 Su. 3) More research is needed on the meaning of daytime and nighttime in 'Wigi Haeng'.