• 대한지구과학교육학회지
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• 제5권3호
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• pp.245-255
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• 2012

The purposes of this research are to analyze preservice elementary teachers' degree of difficulty in classes of seasonal variation and suggest the measures of classes so that preservice elementary teachers can progress classes of seasonal variation effectively. To achieve them, the research was conducted for 90 first graders completing teaching method of elementary science in P university of education from Sep. to Dec. 2012. This research was conducted, based on the results of in-depth interview for 9 preservice elementary teachers who performed classes of seasonal variation, survey on the degree of class difficulty and evaluation of classes on 8 classes theme of Earth sector in elementary science. The results of this research are as follows. The first, preservice elementary teachers had relatively high class difficulty for teaching seasonal variation among the sector of the earth in elementary science. The second, in the evaluation of preservice elementary teachers' classes, the more the subject showed high class difficulty, the more the score of class evaluation was low. The reason is analyzed that high class difficulty reduces teacher's confidence. The third, preservice elementary teachers had insufficient knowledges and concepts which are basically necessary for the classes of seasonal variation. Especially, it was more serious for preservice elementary teachers who didn't learn Earth-science during their high school time. The fourth, it is necessery that concrete and systematical teaching method should be developed so as to improving preservice elementary teachers' teaching method for the classes of seasonal variation.

• Journal of Astronomy and Space Sciences
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• 제37권3호
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• pp.165-170
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• 2020

Muons and neutrons are representative secondary particles that are generated by interactions between primary cosmic ray particles (mostly protons) and the nuclei of atmospheric gas compounds. Previous studies reported that muons experience seasonal variations because of the meteorological effects of temperature. The intensity of neutrons has a typical modulation with various periods and reasons, such as diurnal and solar variation or transient events. This paper reports that cosmic ray particles, which were observed by neutron monitors, have seasonal variations using the daily data at the Oulu neutron monitor. To eliminate the effects of solar activity across time, the daily data were normalized by two different transformations: transformations with respect to the grand mean and yearly mean. The data after transformation with respect to the yearly mean showed more statistical stability and clear seasonal variations. On the other hand, it is difficult to determine if the seasonal variation results from terrestrial effects, such as meteorological factors, or extraterrestrial effects, such as the position of the Earth in its orbit of revolution.

• 대한원격탐사학회지
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• 제26권6호
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• pp.665-673
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• 2010

The role of remote sensing in phenological studies is increasingly regarded as a key in understanding large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for vegetation classification using seasonal variation patterns. The vegetation seasonal variation phase of Seoul and provinces in Korea was inferred using 8 day composite MODIS NDVI (Normalized Difference Vegetation Index) dataset of 2006. The seasonal vegetation classification approach is performed with reclassification of 4 categories as urban, crop land, broad-leaf and needle-leaf forest area. The BISE (Best Index Slope Extraction) filtering algorithm was applied for a smoothing processing of MODIS NDVI time series data and fuzzy classification method was used for vegetation classification. The overall accuracy of classification was 77.5% and the kappa coefficient was 0.61%, thus suggesting overall high classification accuracy.

• Fisheries and Aquatic Sciences
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• 제5권2호
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• pp.114-121
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• 2002

A correction index of catchability (CIC) was derived using a 6 year research data set to examine the seasonal variation in catchability for the night time prawn fishery in Albatross Bay. CIC reflects the composite effect of the monthly variation in size selectivity, emergence­burying behaviour and population density variation of prawn populations. The values of CIC for four dominant species, Metapenaeus endeavouri, M. ensis, Penaeus semisulcatus and P. esculentus, were examined. The value of CIC for M. endeavouri varied substantially and was the highest in August. The values of CIC for M. ensis were high during November to March and the seasonality was weaker than that for M. endeavouri. The monthly variation in CIC for P. semisulcatus reflected the seasonal variation in population density, being high during November to February. These results suggest that the catch ability of P. esculentus is steady throughout the year but it varies greatly on a seasonal basis for M. endeavouri.

• 대한원격탐사학회지
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• 제36권1호
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• pp.1-13
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• 2020

Seasonal changes in river water vary seasonally as well as locationally, and the assessment is essential. In this study, we used the recent technique of post-classification by using the Google earth engine (GEE) to map the seasonal changes in Mahanadi river of Odisha. However,some fixed problems results during the rainy season that affects the livelihood system of Cuttack such as flooding, drowning of children and waste material deposit. Therefore, this study conducted 1) to map and analyse the water density changes and 2) to analyse the seasonal variation of river water to resolve and prevent problem shortcomings. Our results showed that nine types of variation can be found in the Mahanadi River each year. The increase and decrease of intensity of surface water analysed, and it varies in between -130 to 70 ㎥/nf. The highest frequency change is 2900 Hz near Cuttack city. The pi diagram provides the percentage of seasonal variation that can be observed as permanent water (30%), new seasonal (28%), ephemeral (12%), permanent to seasonal (7%) and seasonal (10%). The analysis is helpful and effective to assess the seasonal variation that can provide a platform for the development of Cuttack city that lies in Mahanadi delta.

• Ocean and Polar Research
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• 제29권2호
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• pp.113-121
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• 2007

The sound wave in the sea propagates under the effect of water depth, sound speed structure, sea surface roughness, bottom roughness, and acoustic properties of bottom sediment. In shallow water, the bottom sediments are distributed very variously with place and the sound speed structure varying with time and space. In order to investigate the seasonal propagation characteristics of low-frequency sound wave in the Yellow Sea, propagation experiments were conducted along a track in the middle part of the Yellow Sea in spring, summer, and autumn. In this paper we consider seasonal variations of the sound speed profile and propagation loss based on the measurement results. Also we quantitatively investigate variation of bottom loss by dividing the propagation loss into three components: spreading loss, absorption loss, and bottom loss. As a result, the propagation losses measured in summer were larger than the losses in spring and autumn, and the propagation losses measured in autumn were smaller than the losses in spring. The spreading loss and the absorption loss did not show seasonal variations, but the bottom loss showed seasonal variations. So it was thought that the seasonal variation of the propagation loss was due to the seasonal change of the bottom loss and the seasonal variation of the bottom loss was due to the change of the sound speed profile by season.

• Fisheries and Aquatic Sciences
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• 제4권3호
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• pp.101-111
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• 2001

In an attempt to demonstrate the seasonal variation of the Ulleung Warm Eddy (UWE), in which the UWE changes its shape from a warm core ring in early spring to a warm lens in late summer under the effect of surrounding East Korean Warm Current (EKWC) Water, a simple geostrophic adjustment model is considered. Model results indicate that the buoyancy increase of the EKWC Water and the strengthening of the EKWC towards summer, both of which are typical of this region, are the major factors governing the seasonal variation of the UWE.

• 생약학회지
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• 제35권2호통권137호
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• pp.128-133
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• 2004

Aconitum triphyllum Nakai, the Korean spontaneous perennial herb, is one of the most important materials of oriental drug Fu-zi(aconite) and has long been used as cardiotonic for arrhythmia, analgesic and antiinflammatory drug in oriental countries. Although the plant is widely used for the preparation of aconite, the composition and amount of the toxic aconitine type alkaloids have not studied so far. As the preliminary study for seasonal variation of major constituents in mother tuber and daughter tuber of the plant, the authors tried to elucidate phytochemical characteristics of $C_{19}-diterpenoid alkaloids by $^{13}C-NMR$ spectra and seasonal variation of the alkaloidal contents by high performance liquid chromatography.

• Fisheries and Aquatic Sciences
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• 제6권4호
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• pp.220-224
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• 2003

In order to determined the appropriate processing season of Pacific oyster (Crassostrea gigas), 30 individuals cultured in Kamak Bay on the southern coast of Korea were taken bimonthly 7 times a year, and seasonal variation of edible portion weight, edible portion yield and coefficient of fatness were investigated. There were close relationships between edible portion weight (X) and total weight (Y) and between coefficient of fatness (X) and edible portion yield (Y), which were expressed in regression lines, i.e. Y=0.2709X-1.9094 (r=0.9254) and Y=44.0596X+ 15.1127 (r=0.8485), respectively. From the results of seasonal variation of edible portion weight, yield and coefficient of fatness, the appropriate processing season of raw Pacific oyster was between winter and spring, that is, between December and following April the next year.

• 수산해양교육연구
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• 제24권6호
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• pp.781-792
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• 2012

Seasonal variation of species composition in marine organisms around Oryukdo of Busan was investigated using a gill net between 2009 and 2011. A total of 82 species, 52 families, and 6 taxa were collected during the sampling periods. Species were included two species in Cnidaria, one in Urochordata, 12 in Mollusca, 12 in Crustacea, seven in Echinodermata, and 48 in Pisces. The dominant species were Crepidula onyx, Asterina pectinifera, Ceratostoma burnetti, Asterias amurensis, Anthocidaris crassispina, and Trachurus japonicus. These six species accounted for 48.4% in the total number. Diversity indices were highest in spring 2009 (2.77) and lowest in spring 2011 (1.66). Seasonal variation of species composition and abundance in marine organisms corresponded with the water temperature.